This somewhat randomly popped up on one of my news feeds:

http://www.sciencedaily.com/releases/2015/02/150205095155.htm

"Norwegian lemmings dress loudly and scream even louder to survive"

Hmm, sounds like a real-life version of the proposed screamer skill?

Came across this article.  Haven't tried it myself but seems interesting maybe?  Actual site to go to play: https://archive.org/details/internetarcade (see also https://archive.org/details/consolelivingroom)

I see on IRC that people can make direct links to files they put in DropBox:

https://dl.dropboxusercontent.com/u/43603680/themon0lith.txt

But when I try it out just now with a new free account, the only option I have is to create "share" links for files I upload to DropBox, which look like this:

https://www.dropbox.com/s/3pfxw1g4dmlmbbx/DirectLinkPleaseYouStupidPieceOfCrap.txt

This opens up a preview/download page which is not the same as a direct link (which matters if the file in question is HTML, though to be fair, I suspect DropBox probably won't support direct links to HTML files anyhow even with the first kind of link).  What do I need to do to get the first kind of link?  Is that feature still supported by DropBox with new accounts?

This was originally a private request from Leo, but since PMs here don't allow attachments, and conceivably some other people may also want the graphics in the future, I'm posting them here as attachment.

This is an extension of Luis' "Undamaged Levels" challenge, to the other Lemmings games on DOS.  (I can consider keeping results for other versions too if there're sufficient interest in that.)

I needed to start a new topic so that the list of results can be kept as the first post of the topic instead of buried somewhere on page X.  DOS Lemmings results repeated here for completeness.

Rules summary: beat the level without ever destroying any pixels/cells of terrain originally present in the level.  Destroying the stairs from a builder is fine because it's not part of the level's original terrain (ditto for other types of added terrain, for games like Lemmings 2 and beyond).

(* means one or more glitches are required for the given result.  If placed over the level itself, it means glitches are require for the challenge even without achieving 100%; if placed only over the 100% result, it means the level can be solved for the challenge without glitches, but glitches are required to achieve 100%.)

DOS Lemmings
Fun: 2, 3, 7-12, 14-16, 17*, 19, 20, 24, 25*, 26-28, 29*
    100%: all except 3, 17, 25, 29
Tricky: 1, 3, 4, 5*, 6-10, 12, 13, 22, 24, 26, 28*, 29
    100%: all except 5, 24, 28
Taxing: 2, 3, 4*, 9, 10, 11*, 15, 16, 18, 20*, 22-24, 27*, 28
    100%: all except 2, 4, 20, 27, 28
Mayhem: 1, 2*, 6, 10, 14, 15, 17, 18, 25, 30
    100%: all except 10, 15, 30

Genesis (MegaDrive) Lemmings
(unique levels in bold, Genesis-only achievements on non-unique levels in italics)
Fun: 2, 3, 7-12, 17*, 20, 23, 24, 25*, 26-28
    100%: all except 3, 17, 25
Tricky: 2-5, 7, 8, 9, 11, 14, 21*, 22, 24, 26, 28*
    100%: all except 21, 24, 28
Taxing: 4*, 9, 10, 11*, 15, 16, 18, 22-24, 28
    100%: all except 4
Mayhem: 2*, 9, 14, 17, 25, 28*
    100%: all except 14, 28
Present 7, 9, 11, 22, 30
    100%: 9, 11, 30
Sunsoft: 11, 19
    100%: all

DOS ONML
Tame: 2, 4, 5*, 7, 8, 9, 10*, 13, 14, 15, 17*, 20*
    100%: all except 5, 10, 17, 20
Crazy: 4, 5, 11, 15*
    100%: 4, 5
Wild: 3, 8, 9*, 11, 16, 19, 20
    100%: all except 20
Wicked: 4, 9, 13, 15, 17, 18, 20
    100%: all except 4, 15, 20
Havoc: 10, 12, 15*, 16, 17
    100%: 12, 17

DOS Xmas
91: none possible
92: none possible
Frost: 2, 3, 6, 8, 9, 11, 13*, 16
    100%: all except 6
Hail: 5, 7, 12, 16
    100%: all
Flurry: 1-4, 7, 9, 12-15
    100%: all
Blitz: 1*, 2, 7*, 9, 10, 13
    100%: all

DOS Lemmings 2
[notation: <level number>:<maximum out of 60⁺ you can save without glitches>(<max save with glitches>*)
 highlighted results are gold]
⁺To make it easier to read and compare results, we will consider you can always start off with 60 lemmings in every level, even though in reality that isn't the case w/o using cheats.  According to current records, you only lose a lemming each in Polar 8 and Classic 5.

Classic:  2:59(60*),  3:4,  4:2(8*),  6:4(8*),  10:2(60*)
Beach: 1:60, 2:60, 3:5, 4:1, 5:60, 7:0(1*), 8:60, 9:0(1*), 10:0(1*)
Cavelems
Circus
Egyptian: 4:1, 6:60, 7:2, 10:5(60*)
Highland
Medieval: 4:2, 7:1, 9:60, 10:60
Outdoor: 1:60, 2:60, 3:14, 4:60, 5:60, 6:60, 7:60^*?, 8:1(60*), 9:1(60*), 10:5
Polar
Shadow
Space: 1:60, 2:60, 3:1, 5:60, 6:60, 8:1, 9:60, 10:60
Sports: 3:60, 4:60, 5:0(1*), 6:11(60*), 7:6(8*), 8:2(60*), 9:1(60*) 10:60

DOS Lemmings 3
Note
 - <level number>:<maximum saved out of 20>
 - To make it easier to read and compare results, we will consider you always start off with 20 lemmings in every level.  Remember that due to the reserve system in this game, you receive for example 11 just for getting a single lemming to the exit without anyone else killed (besides the nuke).
 - Highlight means all lemmings saved, including bonus lemmings.
 - Since the game auto-nukes on time up, and there isn't another way to quit without nuking, damage from the nuke doesn't count.  In some cases they may be avoidable by, for example, jumping the leftover lemmings or make them suicide.  Levels where nuke damage appears unavoidable are marked ^!.
 - Since most of time it is impossible to avoid causing disappearing platforms to disappear, that won't count as "damage" as long as it is done via a normally non-destructive action (eg. walking, shimmying, etc.).  Levels where such actions unavoidably occur are marked *.

Classic: 1:20, 2:20^!, 4:20, 5:20, 7:20, 9:20*, 10:20*, 13:22, 14:11, 15:23, 16:20*^!, 19:22, 20:15*, 21:20*, 22:20*, 23:20, 25:21*^!, 27:11*, 28:20*^!, 29:21*^!
Egyptian: 2:20^!, 4:20, 5:21, 10:20^!, 11:20*, 12:20^!, 13:11*^!, 14:23*, 18:20^!, 23:21^!, 27:21*, 28:20^!, 30:11*^!1
Shadow: 1:20, 2:20, 3:11, 4:21*^!, 5:12*^!, 8:20, 9:22*

¹Uses the second glitch listed on this post.

DOS 3D Lemmings

PC Lemmings Revolution
1-1 (100%), 1-2 (100%)
2-1, 2-2 (100%)
3-2, 3-5
4-2 (100%), 4-3 (100%), 4-6 (100%)
5-1 (100%), 5-2* (100%)
6-3, 6-8 (100%)
7-1 (100%), 7-7 (100%), 7-8* (100%)
8-2* (100%), 8-3 (100%), 8-7* (100%), 8-8*¹ (100%), 8-9*, 8-10* (100%)
9-6* (100%), 9-8*¹, 9-10 (100%), 9-11 (100%)
10-2 (100%), 10-5, 10-6 (100%*), 10-8* (100%), 10-10 (100%)
11-1 (100%*), 11-2 (100%), 11-3, 11-6 (100%), 11-9 (100%), 11-11 (100%), 11-12 (100%)
12-1*^1? (100%), 12-2, 12-4

¹Requires this glitch.  Visually the terrain looks undisturbed, but the lemmings will react exactly like the terrain has been dug away.  Probably shouldn't really count as "undamaged", but interesting enough to at least merit a mention here.

Starting a thread to capture all information currently known about file formats for the Lemmings Revolution game, in the same vein as what we documented for a few other Lemmings games in the series.  Interest in Revolution may be low, but then again so are games like L3, but we currently know more about that game's file formats than Revolution.  That should change at some point in the future.

Information given on this thread are not guaranteed 100% accurate, but should be pretty good, and will be updated with corrections if any are reported.

We start off with the BOX file format, which is just a way to package a set of files in a directory tree into a single file, without any compression.  Yeah, not sure why they did that, but they did.   Attached text file is same info as below, just for convenience.

Code: [Select]Lemmings Revolution (PC) BOX format
  documented by ccexplore
 
For some reason, Lemmings Revolution packs most of its data files into a single
large BOX file, instead of simply letting them live as individual files in
individual directories.  There isn't even any compression going on inside BOX
files. Go figure.
 
The format is really simple though.
 
Sidenote: the "Dragon unPACKer" program (as of version 5.6.2 [build 268]) has
major bugs in its extraction code for BOX files. It produces the correct
directory listing, but does not correctly associate each file entry with the
correct set of bytes in the BOX file, at least when I tried it on the files on
my game CD.
 
----------------
BOX format
----------------
 
[NOTE: per Intel convention, all integers are little-endian, meaning that
 a 4-byte hexadecimal integer 0xdeadbeef is stored in bytes as
 0xef, 0xbe, 0xad, 0xde.]
 
Header Info (14 bytes)
0x0000-0x0005: "LEMBOX"
0x0006-0x0009: 4-byte integer, number of files N
0x000A-0x000D: 4-byte integer, offset from first byte after the header to File
               Locations table
 
File Directory (variable size)
0x000E:  N filename entries (variable size), each entry as follows:
        0x00-0x03: 4-byte integer, length L of text string following
        0x04: L bytes in 8-bit ASCII, name of file (including path), no
              0-termination
 
File Locations table (variable size)
        0x00-0x03: 4-byte integer, number of table entries N' (should be equal
                   to N)
        0x04: N' table entries
              each entry is a 4-byte integer, offset from start of BOX file to
              first byte of contents of the file
 
File Lengths table (variable size)
        0x00-0x03: 4-byte integer, number of table entries N" (should be equal
                   to N)
        0x04: N" table entries
              each entry is a 4-byte integer, length of file (in bytes)
 
remainder of BOX file are the bytes for the individual files contained within
 
----------------
Example
----------------
 
Suppose we want to capture the following files in the directory tree below into
a BOX file:
 
AFILE.EXT        (file contents: 0x42)
DIR1\FILE1.ZZZ   (file contents: 0xde 0xad 0xbe 0xef 0xde 0xad 0xbe 0xef)
DIR1\2ND.MMM     (file contents: 0xab 0xcd 0xef)
D2\SD3\Y.CD      (file contents: 0xac 0xdc)
 
Below is one possible encoding. "One possible" because the ordering of files
can be anything--files under the same subdirectory do not have to come up
in consecutive table entries in the BOX file, as demonstrated in the example
encoding below.
 
Similarly, the contents of each file may not necessarily come in the same order
as the file ordering in the tables, because the File Locations table provides
direct offsets into the BOX file for each file's contents, theoretically allow
you to place the contents of each file in any order consistent with the offsets
and lengths given in the tables. That said, in the BOX files from the game, I
think the file contents do come in the same order as the files do in the tables.
 
Resulting BOX file, viewed in hex editor:
 
4C 45 4D 42 4F 58 04 00 00 00 3E 00 00 00 0E 00
00 00 44 49 52 31 5C 46 49 4C 45 31 2E 5A 5A 5A
09 00 00 00 41 46 49 4C 45 2E 45 58 54 0C 00 00
00 44 49 52 31 5C 32 4E 44 2E 4D 4D 4D 0B 00 00
00 44 32 5C 53 44 33 5C 59 2E 43 44 04 00 00 00
74 00 00 00 7C 00 00 00 7D 00 00 00 80 00 00 00
04 00 00 00 08 00 00 00 01 00 00 00 03 00 00 00
02 00 00 00 DE AD BE EF DE AD BE EF 42 AB CD EF
AC DC
 
Below is the breakdown:
 
4C 45 4D 42 4F 58: "LEMBOX"
04 00 00 00: 0x00000004=4 files
3E 00 00 00: offset to File Locations table=0xE (header length) + 0x0000003E
            =0x0000004C from start of BOX file (counting from zero).
 
File Directory, which we know has 4 entries for 4 files
 
0E 00 00 00 44 49 52 31 5C 46 49 4C 45 31 2E 5A 5A 5A:
  "DIR1\FILE1.ZZZ", string length 0x0000000E=14 bytes
 
09 00 00 00 41 46 49 4C 45 2E 45 58 54:
  "AFILE.EXT", string length 0x00000009=9 bytes
 
0C 00 00 00 44 49 52 31 5C 32 4E 44 2E 4D 4D 4D:
  "DIR1\2ND.MMM", string length 0x0000000C=12 bytes
 
0B 00 00 00 44 32 5C 53 44 33 5C 59 2E 43 44:
  "D2\SD3\Y.CD", string length 0x0000000B=11 bytes
 
File Locations table
 
04 00 00 00: 0x00000004=4 files, as expected
74 00 00 00: location in BOX file for the 1st file's contents, which according
             to File Directory is the file DIR1\FILE1.ZZZ
             so contents of DIR\FILE1.ZZZ starts at 0x00000074 from
             start of BOX file
7C 00 00 00: AFILE.EXT's contents starts at 0x0000007C from start of BOX file
7D 00 00 00: DIR1\2ND.MMM's contents @ 0x0000007D from start of BOX file
80 00 00 00: D2\SD3\Y.CD's contents @ 0x00000080 from start of BOX file
 
File Lengths table
 
04 00 00 00: 0x00000004=4 files, as expected
08 00 00 00: DIR1\FILE1.ZZZ's length is 0x00000008=8 bytes
01 00 00 00: AFILE.EXT's length is 0x00000001=1 byte
03 00 00 00: DIR1\2ND.MMM's length is 0x00000003=3 bytes
02 00 00 00: D2\SD3\Y.CD's length is 0x00000002=2 bytes
 
DE AD BE EF DE AD BE EF: these 8 bytes are DIR1\FILE1.ZZZ's file contents
                         located at offset 0x00000074 as specified earlier
 
42: this 1 byte is AFILE.EXT's file contents
    located at offset 0x0000007C as specified earlier
 
AB CD EF: these 3 bytes are DIR1\2ND.MMM's file contents
          located at offset 0x0000007D as specified earlier
 
AC DC: these 2 bytes are D2\SD3\Y.CD's file contents
       located at offset 0x00000080 as specified earlierThere are apparently some programs already available that can extract from BOX files, but they may be buggy and not extract every file inside the BOX correctly, or mix up contents of one file with another.  My documentation here should be more accurate than such programs, sadly.

Mod Edit: Restored attachments.

Since Lemmings and Lemmings 2 have their own glitch thread, I'm starting this thread for glitches on the other games (Chronicles, Revolution, 3D, etc.).  I don't expect as much traffic on those games, so I don't think we really need to create one thread per game like we had for L1 and L2.

I recently started playing Lemmings Revolution and here are glitches I've seen so far (undoubtedly more to come in near future):

Lemmings Revolution (PC)

[edit: this list is currently collected mostly using the patched version of the game, with key game files timestamped 6/26/2000 instead of 4/14/2000.  Once I finish the game I will update the list with all differences I find between patched vs unpatched]

Climbers
Summary: very similar to analogous glitches in original Lemmings, but some with a Revolution twist

• When a climber encounters a ceiling and falls down, it comes away from the wall by one grid-cell, instead of falling down right next to the wall.  See climber-fall-offset.png on this post for a screenshot.
  
• If the terrain that the climber is on is removed, it hoists immediately and converts to a walker in mid-air for one frame.  However, in general the game doesn't allow you to assign most skills whenever the lemming is standing on mid-air (or even on water for non-water lemmings), so unless you want to assign climber, floater or bomber at that exact moment (and likely you can do so at other times instead), this is probably not a very useful glitch.
• If a lemming trapped inside terrain is made a climber, or a climber becomes trapped in terrain, it repeatedly begins climbing, gets stuck, and falls slightly (turning around in the process). It gains one grid-cell in height each time.  It also drifts horizontally to the right as it repeats this maneuver basically every 2 times.  This is because when the stuck climber falls, lands, and turns right (but not if he turns left), he is allowed to walk forward (despite being stuck in terrain!) for one grid-cell before starting to climb again.  This right-only extra walking creates the rightward drift.  So the lemming effectively moves diagonally up-and-right gradually during the maneuver, allow you to pass through walls not just vertically, but horizontally as well.  See this post for a set of zipped screenshots depicting the effect.
  
  [Note that when the stuck climber falls, turns left and climbs again facing left, this transition is directly from faller to climber, so you can't assign non-permanent skills to a stuck climber with him facing left.  Whereas you can with him facing right during his "extra walking" phase.]
  
  
• When a hoister "oh-no" (explosion countdown reaches 0), he ends up one grid-cell away from the wall, and therefore will fall back down.  This works facing left or right.  See this post for a sreenshot.
  
  

Bombers

• reset a bomber:  after a bomber finishes the countdown ("oh-no") but before he actually explodes, you can assign a non-bomber, non-permanent skill, and this will "reset" him so he doesn't explode.  This works on blockers about to explode too, so you can free a blocker this way.
• The same glitch above also works with lemmings about to explode due to nuking, after the nuke countdown finishes when the lemmings start their "oh-no".
• If a lemming transforms to "oh-no" just before he hits the ground, he will not splat regardless of how high the fall was. Together with the "reset a bomber" glitch, you can survive a high fall without floaters by using a bomber plus a suitable spare skill. (reported by LemSteven)
• You can use the "reset a bomber" glitch on a right-facing climber who is in the midst of climbing a wall.  For some reason, this does not work for left-facing climbers.  This is why it is possible to save 100% on "Quick as you can", but not on "Can't get there from here". (LemSteven)
• if you use the "reset a bomber" glitch on a lemming entering a teleport, the lemming won't enter the teleport, and he will start walking in a strange manner.  He still behaves like a regular walker, though.  If he returns to the teleport later, he will enter and return to normal. (LemSteven)
• You can use the "reset a bomber" glitch on a drowning lemming.  Normally this isn't very useful since being in water, you can't even assign any useful skills, and even if you time it just right so that the lemming is at the very bottom (making skill assignments possible) when it "oh-no", there just isn't much you can do down there that doesn't end up re-drowning the lemming eventually.
  
  However, there is one awesome exception:  if you drown an upside-down (ie. antigravity) lemming in normal water, it will fall up and away from the water surface (since after all, up is down for antigravity).  This is shown in screenshot upsidedown-lem-triggering-objects.png (bottom-right) from this post.  Hence if you can arrange for the lemming to "descend" onto dry land during its drowning, and have it "oh-no" in mid-descend, he's ready to be reset once on dry land, for further usage.
  
  A drowner reset this way will have the following odd behavior:
  
  • For the skills of bashing, mining, building, and digging, the lemming will only carry out one full cycle of animation (ie. one stroke, one build brick, etc.), and then the lemming just stops and freezes.  The "frozen" lemming is still considered in the middle of carrying out the skill (so for example, if it is building when it freezes, you can't just assign another builder, you have to assign some other skill first, and then you can assign a builder to force it to build another brick).
  • Fortunately it can walk, climb, fall and float without "freezing".  Of course, getting it to start walking can be tricky, as you start the lemming off via reset-a-bomber (so it has to start off performing some sort of skill).  If the lemming faces left, using the "left builder block to walk" glitch is probably the most efficient way to revert it to walking.  Otherwise, I think if you can arrange for it to revert to walking or falling as the natural result of carrying out a skill for only one cycle, that'll probably work too.
    
  • The walking animation looks funny.  Basically the lemming often stops animating as it walks, so it kinda just slides around.
  • The lemming retains the translucency of drowning lemmings at all times.
  • The lemming can still trigger all objects in this state, including the exit, blockers, and the antigravity pad.
  • If the lemming is upside-down and tries to fall off the top boundary of the level, it will instead get stuck there without dying.  You can't do much with it though, since it's still considered in the middle of falling/floating, leaving you with very few useful skill assignment choices.  You can kill it with a bomber or nuke if needed.  This glitch doesn't work with the bottom boundary as the lemming, even in its weird state, will go splat off the bottom boundary.
• When a lemming explodes, the game renders a sort of "gut splatter" onto the surface of the cylinder, near where the lemming is.  This splatter will eventually fade out.  But while it is being displayed, it may obscure other graphics that extend far enough into the cylinder surface.  For example, it will make a retracted wall look like some of its squares are gone (see screenshot explosion-graphical-artifacts.png from this post).  This is purely graphical and does not actually affect whatever objects are there behavior-wise.  It may even conceivably be dependent on your graphics card.

Blockers

• (glitch arguable) When a blocker is assigned bomber, as soon as the countdown finishes the blocker no longer blocks (other lemmings can pass through).
• In some cases it's possible to get a single lemming to pass through a blocker, by assigning him a skill like basher really close to the blocker, just before the lemming turns around.  More investigation is needed to work out the details, but I suspect it may have to do with the game grid-aligning the position of the lemming to fit with the skill action.
• Mechanics of blocker fields:  to really understand all the unexpected cool things you can do with blockers, such as blocker-stacking, you need to understand how blockers work in the game.  Blockers work in Revolution by setting special "blocker-field" status to the vertical column of 4 grid-cells at the blocker's position, starting from head down to feet of the blocker lemming.  Grid-cells with blocker-field status (shortened henceforth to "blocker-cells") has the following properties:
• Blocker-field status is orthongal to other grid-cell status, rather than exclusive.  This means you do not have "steel-canceling" or "trigger-canceling" glitches (as far as I know anyway, I haven't tested all combinations) like in original Lemmings.  A grid-cell can simultaneously have both blocker-field status as well as other existing statuses like steel, one-way, or whatever.
  
• However, blocker-field status is not cumulative, meaning that if you set 2 blockers at the same grid-cell position, and free only one of them (eg. via the "reset a bomber" glitch, and doesn't matter which one), the moment that lemming is freed, the grid cells in question will have blocker-field statuses cleared, despite the fact that you still have that 2nd blocker in the same grid-cell position.  Simply put, while the 2nd blocker will remain a blocker, he will no longer actually block other lemmings from walking through him.  See this post for a screenshot of this.
  
• Blocker-cells can be landed (even splatting) and walked on like regular terrain, allowing such tricks as stacking a bunch of blockers vertically, or to use a bunch of water-lemming blockers to "cover up" the water surface creating a safe path for non-water lemmings to walk on.
• Walker lemmings (even those assigned climbers, obviously) attempting to walk into a blocker-cell, will turn around instead.
• Blocker-cells can even be climbed on like regular terrain. Because walkers are turned around by blocker-cells, you need to have an already-climbing climber to see this; thus the best way to test this is to set a blocker at the top of a climbable wall.  See this post for a screenshot.
  
• Terrain (eg. build brick) inside blocker-cells cannot be removed by bashing, mining or exploding, kinda like steel.
• However, blocker-cells can be removed by digging!  You can thus dig away the blocker-field status (in addition to any actual terrain in the grid-cell) making the blocker ineffective, without actually freeing the blocker.  (See this post for a screenshot.)
  
• Builders do not get turned around by blocker-cells, but the usual terrain rules causing the builder to stop building, works with blocker-cells as well. (Thus when building really close to a blocker facing it, the builder basically stops building as if running into a wall.)
• Miners are affected by blocker-cells. It appears that at the moment the mining stroke begins to remove terrain ahead, if the grid-cell it tries to clear terrain from has blocker-field status, the miner gets turned around (and the terrain not removed from the grid-cell).  I think this applies on each animation frame of a miner stroke that removes terrain, not 100% sure though.

Builders

• left builder block to walk: assigning blocker to a left-facing builder will cause it to walk instead of block.  You don't even need any special timing to do this.  Doesn't work with right-facing builder.
  
• (glitch arguable) given the mechanics of how builders work and how blockers work (see above section on blocker-field mechanics), it's possible to build over a blocker in such a way that other lemmings walking up the bridge will still be turned around by the blocker underneath, even though the builder is unaffected by the blocker.  See this post for a screenshot.
  
• When building left, during the short pause ("wait") after the lemming runs out of build bricks, you can't immediately assign him skills until he starts walking.  Whereas when building right, you can assign as soon as the wait phase starts.
• (glitch arguable) The water surface acts as a ceiling for an upside-down (antigravity) lemming building "up" against it.

Bashers

• A basher can remove terrain behind him.  Be especially careful when assigning a builder behind a basher. (reported by LemSteven)
• On the level "Something fishy", when a lemming is bashing through an area and a builder starts to build through the area that was bashed through, the built steps will start to disappear slowly behind him, in a manner that looks like an invisible lemming is bashing through them (the actual basher is very far away from the builder).  This doesn't happen if the basher is finished and no longer bashing.  (reported by thick molases)

Miners
Summary: remarkably, the infamous miner glitch from original Lemmings lives on in this game too!

• basic miner glitch:  Miners are positioned one grid-cell too low during the few frames of their animation when terrain is being removed. This makes it possible to have the miner fall through the floor while leaving it intact for other lemmings to walk on, by assigning a blocker, bomber or digger at the right moment. (It takes multiple frames to remove all the terrain during a mining stroke, and terrain is removed from top to bottom.)  See miner-glitch.png screenshot on this post for more details.
  
• At the very frame when a miner stroke just breaks through (you can't be late, or you won't be able to assign skills anymore until he finishes falling), assign builder to the miner, and the first build brick will leave a gap in the terrain.  See miner-glitch-2.png screenshot on this post to see exactly what I mean.  This only works facing right; facing left, the build brick is positioned differently and does not leave a gap.
  
• In some terrain setup where a left-facing miner is standing on terrain only one grid-cell thick, but the next "step" down has enough terrain so you aren't breaking through the floor, the miner automatically stops mining anyway after the mining stroke. He doesn't fall through the terrain though, so it's not the same as the basic miner glitch.  See miner-glitch-3.png on this post for a screenshot if you're confused by my poor description.  Appears to only work facing left (in the symmetric situation facing right, miner continues mining without interruption).
  
  

Interactive Objects

• (glitch arguable) For some objects, you can easily avoid triggering the object merely by getting slightly below floor level of where the object rests.  For example, if a lever switch or teleporter is not resting on steel, you can simply dig down once and then bash through the entire length of area that would trigger the object.  This lowers the floor enough for you and other lemmings to bypass the object without triggering it.
• direct-drop to exit: lemmings falling onto the exit's trigger area will exit if there is terrain under it, even if they would splat from the fall if the exit wasn't there. In fact in some cases, you may actually even see and hear the lemming first go splat, but then hear "yippie" and the number of lemmings saved go up.
  
• Lemmings falling directly onto exit trigger can exit, even if the exit trigger is in mid-air with no terrain to actually land on.
• aborted exit jump: when a lemming is in the middle of jumping into the exit balloon, you can abort the jump by making the lemming "oh-no", or simply assign skills to it.  If it is done too early during the jump, the lemming just ends up re-triggering exiting again.  However, once its jumping has moved the lemming sufficiently farther away from the cylinder's axis than the normal distance, this will apparently mess up the object collision detection, and the lemming will no longer re-trigger the exit after the jump is aborted.
  
  In this state, the lemming will react to terrain normally and carry out most skill actions normally, but:
  
  
  • The lemming won't trigger any objects! (eg. this and other exits, water, switches, etc.).
  • The lemming is stuck with the special 3D orientation of the exit-jumping (ie. basically 90 degrees off from normal orientation, ie. facing directly into or away from camera), as well as the abnormally farther distance-from-axis.  In other words, it moves funny.
  
  See screenshot aborted-exit-jump.png on this post for examples of the above effects.
  
  To revert the lemming back into normal state, assign it blocker.  A blocker will gradually move itself back towards the cylinder's axis (this is a normal side effect of blockers) until the distance to axis is back to normal.  Free the blocker and it's back to regular behavior.

• During a lemming's jump into the exit balloon, its vertical position is in fact continually updated according to where it is at the jump.  In particular, at the final parts of the jump when it is dropping into the balloon basket, his vertical position will lie below floor level of where the exit trigger is.  Together with the "aborted exit jump" glitch above, you can take advantage of the vertical positioning as in these examples:
  
  
  • If the lemming goes "oh-no" at this point, and the floor is thin enough so the lemming, being below the exit trigger, is now in mid-air, he'll fall.
  • You can start digging or bashing from the below-exit position, if the skill assignment is permitted (ie. if there is terrain below the lemming's feet, as required in order to assign many of the skills)
  
  (This post has screenshots for the above effects.)

• (glitch arguable) Triggered objects don't care whether the lemming is upside-down (ie. from an antigravity device) or not, so it's possible to achieve funny/unexpected things with upside-down lemmings like jumping into an exit balloon while upside-down, drowning in (normal) water upside-down (with the drowning corpse floating away from the water, as per the lemming's inverted gravity), etc.  See screenshot upsidedown-lem-triggering-objects.png in this post for some examples.
  
• no splat on water (glitch arguable): water lemmings can land safely on water from any height, even heights that would splat when landing on normal terrain.
  
• underwater mining etc.:  assign a water lemming miner while he's on water, and he will move diagonally downwards into the water just like mining through regular terrain.  However nothing is actually destroyed (ie. the water surface remains exactly where it is at, there is no actual mining tunnel created in the water).  Once the lemming starts walking, he will immediately snap back up to the water surface.
  
  You can also bash and dig underwater with similar effects, although the game doesn't let you assign digger when standing directly on top of water (you have to start on regular terrain, like building one brick on water surface and then dig from there).  Building underwater just lets you build one brick and then you stop, as if the lemming is stuck inside normal terrain.
  
• The "underwater mining" glitch above also works with acid lemmings on acid.  However, the resulting behavior is rather different, in that unlike water, the acid can actually retain the tunnels created!  Moreover, lemmings react to acid material a bit differently from regular terrain.  The overall behaviors are complex enough that, due to my limited testing so far, I will not attempt to (likely incorrectly) summarize for now.  See screenshot acid-tunnel.png on this post to get a taste of the weirdness.
  
• You may trigger an underwater crab merely by assigning a skill while near it, even if you can walk across the water surface safely without triggering it.  For an example, try assigning basher or blocker in the level "Kriss Kross" (5-2) near the crab.
• (glitch arguable, but definitely annoying) The game's mouse-handling prioritizes entrance objects over lemmings, so it's easy to mistakenly change the entrance release rate when you simply mean to assign a skill to a lemming near an entrance.  Zooming in helps a little.

• The entrance "box" object is a sort of special terrain, with the following behavior:
  
  • A walker can walk on/inside it, but a faller or floater will fall through it.
  • To confuse matters further, a falling/floating "oh-no"er can land on/inside entrance material, though this is not as useful as it sounds (see below on skill assignment).
  • It doesn't act as a wall for walkers though.  For example, if you build to mid-height of the box to reach the box, walkers won't turn around at the sides of the box, or try to step up or climb up the sides.  Instead you will just walk through the sides and through the entire length of the box at mid-height.
  • And yet, a builder will react to the entrance box like it is a wall or ceiling.
  • It is indestructible (I tested all removal actions including basher, miner, digger and exploder).  Actually, an exploder can affect the graphics of the entrance, but not the lemming-interaction behaviors.
  • It is not considered normal land for skill assignment purposes, so basically you can't assign most skills while standing on entrance material.
  
  The entrance-interactions.png screenshot in this post includes many of the behaviors discussed above.
  (Note: the "flaps" of an entrance are not special and basically has no interactions with lemmings AFAIK.)

• Only walkers are affected by an anti-gravity device; lemmings performing most other actions (even things like "oh-no") are unaffected.  The easiest application is to pass through an antigrav by air-bashing.
• The teleporter "beam" is turned on whenever one or more lemmings begin to enter/exit a teleporter on one side, and normally the beam turns off when all lemmings have gone through to the other side (for the entering teleport) or when all lemmings have finished exiting (for the exiting teleport).  However, if a lemming explodes in the middle of entering or exiting the teleporter, so that there's a lemming that never technically went through to the other side or never finished exiting, this will result in the teleporter beam staying on forever. (reported by thick molases)
• (glitch arguable) A lemming cannot re-trigger a teleporter until he has left and re-entered the teleporter's area of detection.  So for example, if you set a blocker at the immediate exit point of the exiting teleporter, you can trap the exiting lemmings within the exiting teleporter's area of detection, and they won't be re-teleported (simply walking past the teleporter with no effects) until they can leave and re-enter the detection area.  See screenshot not-teleporting.png from this post if still unclear.
  
• A timed door normally only allows a predetermined number of lemmings to pass, but you can sneak more through if you've got them bunched up tightly enough.  (reported by LemSteven)
• Retractable walls will turn around a builder very similar to how blockers turn builders in original Lemmings.  This works even when the retractable wall is actually in the retracted (opened) state (ie. not a wall for walkers). (LemSteven)
• Non-water lemmings can walk on water for an extremely short distance without drowning. (LemSteven)
• When an acid pool is drained, the lemmings don't fall into the drained pool, but will instead walk across the top.  The exception to this is if an acid lemming is walking on the acid while it is draining, in which case the lemming will go down with the acid. (LemSteven)
• If a sped-up lemming enters another speed up pad, it reverts to normal speed but retains the speedy blur behind him. (reported by thick molases)

Miscellaneous

• If the timer runs out, it seems the game will determine win/lose based on number of lemmings at the moment the timer hits 0.  Even though the game will run on for a few more seconds afterwards, and any additional lemmings that exit afterwards will be included in the post-level screen's count of lemmings saved, the game will still say you fail the level if you hadn't saved enough when timer hits 0.  (See screenshot out-of-time.png from this post.)
  
• At a fall distance equal to digging 30 steps down, some lemmings may survive the fall while others go splat at the very same fall (like, literally at the same location).  I'm still not 100% sure of the details, but based on some testing, it feels like the later (in terms of time elapsed) the lemming comes out of the entrance, the more likely it will survive such a fall.  But even then it's not like there's an exact cut-off before which all lemmings splat; instead it kinda alternates with no obvious regularity, except for splatting less and less frequently.  See safefall-imprecision.zip from this post for some example screenshots.  I did test that fall distances of 29 steps and 31 steps do behave consistently (ie. all survive for the former, and all splat for the latter).
  
• Sometimes when you scroll around the level, you may cause a lemming to somehow pass through a blocker.  Exact circumstances still unclear (only happened twice to me so far). I think for this to happen, the level can't be paused when you are scrolling, but I'm not sure.  I've also encountered one time where this happens merely when I fast-forwarded the game for a bit, without any scrolling.
• Once I had a climber get stuck for no apparent reason.  I can't remember what level it was but it was climbing up a straight wall and when it reached the top instead of falling, it stopped but appeared to keep climbing, even though he wasn't getting anywhere. I couldn't assign it any skill anymore, not even bomber.  It stayed there "climbing in place" for the rest of the duration. (reported by thick molases)
• More than once I've had lemmings just vanished into thin air. Levels I remember seeing this are "Reduce and Simmer" and "Don't let them out".  In the latter I think it happened at a certain spot where a lemming was bashing near the exit balloon, and it just disappeared with no splat sound or graphic or anything. I couldn't investigate it because every lemming that got near that particular spot vanished. I can't remember if the ticker reported a change in the number of lemmings.  In "Reduce and Simmer" I had a climbing lemming reach a wall and it began to climb, but stopped halfway up and appeared to "mount" the wall when it wasn't at the top, then go into the terrain and vanish. It was always at a particular spot so maybe these are glitches with the levels and not in the game in general. (thick molases)

outside a level
These are annoying glitches/flaws I've run into during the non-level-playing parts of the game.  Some may be due to running the game on versions of Windows higher than when the game was released (ie. post-Win98).

• The game doesn't save your audio settings (volume of music and sound effects), you have to set it again each time you play the game.
• Using Alt+Tab to switch out of and back into the game almost always crashes the game when you try to go back into it, unless you're inside a level when you switch out.
• Even when inside a level, using Alt+Tab to switch between the game and other programs leads to loss of music in the game, until you restart the level or go back to pick another level.
• On Win7 I can't even get music to play at all no matter what.
• On Win7, the first time you're on the main menu right after starting the game, no text is displayed on the menu buttons.  This corrects itself after you started playing a level and then go back to the main menu.  Does not repro on XP.
• At the post-level screen where it shows you how many you need and how many you saved, the text is too dark, it's almost unreadable.

Things have been crazy quiet around here the past few days.  Almost miss the SPAM...not!

Sounds like everyone's preoccupied with other non-Lemmings stuff going on in their lifes?

For me, unfortunately it's just work stuff.   On the plus side, most TV shows I care about wrapped up already for the season [it has to do with how broadcast TV are scheduled in the US], so theoretically it should free up a little more time for me to do other stuff.