The reverse levels challenge thread

[finlay]

Oh well. Do I at least get a cookie for possibly discovering a glitch? 

Anyway, would it be possible, minimac, to actually post underneath what extra skills were used? We could maybe then have a go ourselves and try to beat it...

As for Wicked, since nobody's started it yet:
1 requires no skills (like Fun , although it's impossible to get to the top exit.
2 & 3 are impossible
4 is possible via any of four exits – although significantly harder to get them all to go to the NW exit.
I can't work out a way for 5, since there is only 1 bridge (which is enough to get them there from the entrance platform, but some will inevitably fall off)
6 might be possible, if you are able to pull off a bomb-squad style manoeuvre with bomber timing (there are also a few miners which can serve a similar purpose) – however I'm not very good at this and not sure how many builders would be necessary. You can trap the crowd with blockers at the bottom, however, unlike Wild 1 (which I'm pretty sure is impossible)
7 is one of the few ONML levels without builders and is naturally impossible.
8 is possible, and a nice little puzzle as you can only lose 5.
9 is unsurprisingly possible.
I thought 10 was possible, but the death drop was higher than I thought. The solution may yet be salvageable, though, not sure.
11 doesn't look possible to me, and it's a bit long for me to want to attempt.
Fairly sure 12 is impossible
13 is possible.
14 is impossible for me, but I suspect it may be possible to slide up the wall on the left.
15 is possible
16 is impossible
17 seems impossible
18 seems like it'll need a way of turning the lemmings around on the right. Don't quite want to declare it impossible just yet.
19 is impossible.
20 doesn't seem to have enough builders. (and then there's the issue with the exit having to be slightly buried so that it'll save properly in Lemmix!)

[Minim]

By the way, how did you solve We all fall down in the end? What skills did you add?

I realise that the entrances for the Fun/Tricky version and the Taxing/Mayhem version have different y-coordinates. Apologies for that. I'll have to re-work those levels tomorrow so that they look similar. Anyway, for the Fun/Tricky version, I took the right side and I think I used 10 builders for that method.

[Clam]

Oh well. Do I at least get a cookie for possibly discovering a glitch? 

I think only ccexplore can tell you for sure whether this glitch/trick is 'new'. He's been around a lot longer than I have

As for Wicked, since nobody's started it yet:
[...]
2 & 3 are impossible

Wicked 3 is not impossible, thanks to yet more sliding magic.

[finlay]

you and your sliding glitch...

you see i'm still mostly thinking in terms of 'conventional' solutions...

Anyway, confirmed Wicked 10 as possible.

[Clam]

you see i'm still mostly thinking in terms of 'conventional' solutions...

There's nothing wrong with that, conventional solutions work just fine for most levels.

It seems reasonable that the sliding glitch is going to see a lot of use in this type of challenge. There's a tendency for levels to start at the top and work downwards (the alternative usually being heavy building, which would be boring to do all the time). Reversing those levels means you start at the bottom and work upwards. The sliding glitch can be a very skill-efficient way to move lemmings upwards. It makes sense.



Continuing on with more improvements to Wicked:

5: Annoyingly, I couldn't quite pull this off either. At most though, you can get by with 1 added builder.
6: Possible. To start with, I used sliding to get halfway up, but it turns out you don't need to do that. This solution also uses no bombers at all
(I did 10 since my last post, but you beat me to it. Good find )
11: Me and my sliding glitch . It's possible with the regular skillset.
16: Pretty clearly impossible with the regular skillset, here's a fairly simple method using 5 extra skills, 1 blocker and 4 builders. I haven't looked too hard for other methods, but nothing stands out as a better option.
18: Not too difficult, you just need to stack some bridges on the right to contain the crowd.
19: This one works out very nicely with 1 added blocker.


For 14, it looks like you need extra skills just to reach the left wall, let alone slide up it. It might still be the best option (as far as fewest added skills), I don't know yet.
For 20, I suspect the most skill-efficient solution involves sliding into the exit, so it matters not that it's buried
EDIT: Changed my mind. I found a solution with 1 builder added, and no glitches. There's a 'spare' digger, so it still doesn't matter that the exit is buried

[ccexplore]

Oh well. Do I at least get a cookie for possibly discovering a glitch? 

Here. (Surprisingly difficult to Google for blue and green cookies that I'd want to eat.  The above ain't it. )

But yes, while I can't say my memory's that great, I do believe you have reported a glitch that hasn't been reported before.  Good work!

<now go back to game disassembly to see how this is happening...ah ha> Basically this is caused by a discrepency between how the game does the "too close to the top" check, and the vertical position it resets the lemming into in order to keep it from going further up.  It may literally be a mistake between "less" vs "less than or equals".  Basically something like this (except it's not exactly 10 and 9, but I can't be bothered now calculating the actual values in screen coordinates):

if (y <= 10)  // smaller y is nearer to the top
{
    turn lemming around;
    y = 9;
}

Resetting the y is clearly an attempt to keep the lemming in check, but the discrepency between the check for the condition and the reset value pretty clearly leads to the behavior observed, with the lemming bobbing up and down slightly while in its stuck state.

[edit: neglected to mention one addtional detail (though pretty obvious if you try to figure out how the glitch works given what I already told):  the "check and reset" above only takes place for a walker if he's maintaining or moving higher in vertical position.  If the lemming takes a small step down instead, there is no "check and reset" for the top boundary in that case (which indeed is kind of unnecessary if not for the discrepency at the heart of the glitch).  This is why the lemming only gets pinned to y=9 every other frame (ie. bobbing up and down), instead of every single frame.]

[Clam]

Crazy 13 is possible, and made a lot easier because of direct drop (so it only needs a blocker to turn the lemmings round for instance).

That's Crazy 14. 13 is considerably more difficult than that


Here's some more Crazy results:

2: The best I've managed so far is +5 skills, by mining and building through the exit platform.
4: Done with +3 skills, one each of blocker, miner and digger.
6: Annoyingly close to being doable with one skill added, but in the end couldn't do better than +2 builders.
16 and 19 are possible with the regular skillsets, the latter with no small amount of time limit rage.

[finlay]

(I did 10 since my last post, but you beat me to it. Good find )

Same way, or different?

[Clam]

Pretty much the same, including exploiting the poor steel object placement (thank you, Lemmix editor! ), and building into the chain.

[finlay]

OK, here are some Wild levels, starting with the second half:

11: impossible. Best I could manage was 13 extra builders, because you have to build all the way up a tiny gap.
12: possible
13: impossible, and probably very difficult to solve in the time limit. Not sure of the best way to go about it.
14: possible - you have to use bombers to get past the spike traps, however, because you have quite a limited number of builders.
15: impossible, again not sure what you'd have to add to make it possible.
16: impossible, but adding 1 basher allows you to take the route over the water traps.
17: may be possible but I don't want to attempt it because if it is it'll be hard to pull off.
18: again, I don't want to attempt it. I don't think this one is possible, though – eg you'll have to waste a lot of builders to make the right hand side impassable.
19: possible
20: seems to need quite a few more builders than you're given.

8: with a 1-minute timer, may be permanently impossible. Certainly the obvious route of building up took too long.
6: had to add 1 climber in order to get out of the entrance chamber and release (weren't enough builders otherwise)
5: this level pissed me off a little bit because it looks like it should be possible to build up to the left, but with the 4 builders availble, you're 1 goddamn pixel short! Argh. Anyway, it's trivially completable with 1 extra builder, in that case...
4: it may be possible, although the solution I was using ran into trouble and I couldn't complete it without 1 extra builder. I didn't manage to pull it off, however, not quite, because I had trouble releasing the blockers at the beginning. (my laziness/incompetence, not the level)
3: possible, although the exit being buried is annoying (there are plenty of spare diggers but it's easy to forget!)
2: Not sure, haven't tried it but I don't think there are enough builders to get up to the exit
1: Pretty sure it's impossible without blockers to hold the crowd. Haven't tried it though. Like "Pop til you drop", should be possible without bombers (there are only two layers of bubbles to get through)

[Minim]

I've had a turn myself at this difficulty rating as well, and on the ones where you didn't want to attempt I've solved Wild 17. Both that and Wild 14 have turned into beautifully crafted puzzles. On 18 I came close, but not close enough to get through. Looks like we need help saving builders with that special technique which I guess has been mentioned here. It may be possible with 1 extra basher I think. But anyway, Here's a hint on how to trap the lemmings in 17:

A blocker should be set first, followed by the second lemming mining and building to the left (without going off the bricks) to hold the others back. The third lemming is your worker. The blocker can be freed by mining and building to the right (again, without going off). It is quite a tight space! After your worker has made a path, some luck on timing is required as you try to get the lemmings out of your created pit.

[finlay]

Crazy 13 (It's a trade off): I was going to say 20, which is 18 climbers, 1 blocker and 1 extra builder – however, because the level only requires 50% (ie 10 lemmings), the true total is 11 – 9 climbers, 1 blocker and 1 extra builder.

Also I suspect Crazy 17 is permanently impossible, because I can't even get close to the exit with the solution I'm trying to use. I don't think you'd be able to build over the water, which would be a bit quicker than bashing through the ceiling as you do in the forward level.

[Clam]

My turn on Wild:

2: Possible by sliding up the pillars before the exit. Another option might be using Tame 20 into one of the floating platforms, but if anything the sliding method is easier.
4: Possible, and turns out to be a very nice glitch-free puzzle
6: Again, possible with default skills, and another nice puzzle. (That trick may even be worth making into a custom level )
8: Done with +3 builders, would be 2 if there was another 15 seconds or so available.
11: Another great puzzle (albeit glitchy this time), with no added skills needed.
18: Possible. Using ccexplore's improved builder-stacking method, I ended up with 2 builders spare, so even basic builder stacking will do (as long as you start stacking in the right place ).


Also, because I detest the word 'impossible' when it relates to Lemmings challenges, I've completed Crazy 17 with 11 edit: 9 skills added (6 builders, 2 bashers, 1 digger). Even with sliding, this one only just squeaks in under the time limit

[finlay]

Re: 6 – Dammit, I always forget about the possibility of an outside route...

[Clam]

Improvements to the first half of Havoc:

2: I found a way through the ceiling with just 1 basher added. (Steel placement fail again )
3: Done with +3 skills, 1 blocker and 2 builders. This is an awkward one, you can possibly save a builder but it takes a lot of other skills to do so.
5: Done with +2 builders, with great difficulty, unfortunately you can't mine past the exit trigger which would save another builder and a whole lot of effort. (Even in reverse this isn't one of my favourite levels )
6: Beat this one with the regular skillset
9: By building through the edge of the starting platform, I managed to milk enough distance to save a builder. Ended up with 2 added skills, 1 builder and 1 digger.