Okay, some comments.
First, the version of Lemmix player on Eric's website is a bit outdated - I'd reccomend using the one
here. Since you say you avoid glitches and stuff, you could possibly even look at using
NeoLemmix for your pack.
If you'd like, I can build a player for you (in either Lemmix or NeoLemmix) that includes all your level files internally, so that you just need to distribute the one EXE file (and the readme, of course). This would also mean that some other things can be customised, such as the title screen logo and the difficulty rank signs and names.
Now, onto the level-specific stuff. I've only played Fun so far, and won't comment on
every level:
Fun 5 - It's a bit of a jump from the previous levels, but was definitely creative and fun.
Fun 6 and Fun 7 - These are both great examples of levels that look tricky, but turn out to be quite easy (which they should be for early-Fun position), great job.

Fun 8 - I like both the variety of solutions to this level, and how you've made the trap barely visible but in a way that, if spotted, clearly can be identified as a trap.

Fun 9 - The exit somewhat hanging over the sides of the block looks a bit strange. The solution to the level is nothing really special, but the visual design of it (apart from that thing with the exit) is really neat!

Fun 11 - Pretty nice level!

Fun 12 - This is cool! I like how at first it would appear to be an annoying fidgety build-against-diagonal level, but if you look closer there's a way around all that - and the level title also hints at this.

Fun 13 - This is a really interesting level!

Fun 15 - It appears the steel areas aren't placed too well - though to be fair, under non-Neo Lemmix, that is quite hard to get right, and my packs don't really have it perfect either. Nice level though.
Fun 17 - Another level with a really interesting design!

Fun 18 - This seems to be the first level that requires a bit of clever thinking to it - and still very well suited to its position. A nice level for sure!
Fun 19 - Simplistic design but quite a fun one.

Though... the screen start position seems a bit weird?
Fun 22 - A neat design, though it does take a bit of time to execute...
Fun 24 - Another cool design, and fairly fun to play too.

Fun 27 - Neat design. While this is a general thing with this pack (so far), I really like the variety of methods that can be used for this level!
Fun 28 - Screen start position is a bit strange on this one too. Not a bad level though.
Fun 30 - A very nice concept, a pretty cool design, and I'd say a good level to finish off Fun with.

Some general comments post-playing Fun:
- You've done a great job on avoiding tediousness. There is the odd level that can be a bit like that, but precisely because they're rare (two levels out of the entire rank that I might consider to be a bit on that side), they don't get annoying at all.
- I really like how the levels have a variety of solutions and do indeed maintain a similar feel to Fun from the original game. Most can be solved with a "block off the crowd and use a worker lemming" approach, which is good for newer players; while at the same time there are other options available, which is good for the more experienced players who get a bit tired of doing that every level.

- There's a slight purely-graphical issue in general with your one-way arrows. One-way arrows should generally be set with the "only draw on terrain" flag set ("Gr" in LemEdit, "Only on terrain" in Lemmix editor), that's how the original game has them to disappear when the terrain is removed.
- I'd also say you've done a pretty good job in varying the graphic sets you use, this can be pretty hard to do when you don't have too many to work with (like in this case, where you're only using the Orig ones, not the OhNo ones).
I'll probably look at Tricky later on today. Here's my replays for how I solved Fun - though as I noted, in a lot of levels I was able to find a variety of solutions (which is definitely a
very good thing for Fun). Note that I used the updated player that I linked in the previous post, so try with that if any replays don't work (although in general I've never known any compatibility issues between the two, apart from in some levels with three entrances as the older version doesn't have the correct release order under a certain mechanics set (not sure off-hand which one it was wrong in)). Also note that one of them it may look like it's stopped mid-way, but this is actually because I'm waiting for the last lemming to become the new worker after using the terrain to naturally trap the crowd - wait for him to come along and the action will resume.
