Fewest repeats of the same skill to beat levels.

[Proxima]

All of Tame, with the obvious exception of 13, can be done with 1 of each. Level 19 is the only one that's really a challenge.

[ccexplore]

Now that being said... for Fun 15, it's possible to get into ceiling using only two builders, right? You'd then two (well, not entirely impossible with one, but I doubt you could pull it off with a 3-of-each-skill limit whereas 4 might be reasonable especially given the extra builder) to slide up the last pillar... obviously, prior to completing the path, you use climbers to get your lemmings up there instead of sliding. I'm NOT going to try and pull this off, but any obvious problems with the theory?

I can answer this one. The two-builder route depends on other lemmings mining while the bridge is in progress, to take away ceiling pixels so the builder doesn't stop. That makes it unusable for this challenge, as you need too many climbers and miners.

I have actually been looking at this one, and I can tell you that the ceiling mining in Clam's solution is not optimized and can actually be done with no more than 3 miners, by having the 2nd builder start building from the left edge of the step instead.  See attached for proof.  This not only makes 4 an almost certainty for this level, but actually leaves 3 just within the realm of possible (obviously one of the climbers cannot be a climber anymore in that case...).  It'll likely take some time though before I can get "3" to actually work, if it does turn out to work...

================

In the meantime here's a "3 (glitch)" for Tricky 13 instead, courtesy of my solution from the "What skills can't you live without?" challenge.

[Proxima]

Excellent! Meanwhile, here's what I have so far for Crazy:

Crazy 1: 1
Crazy 2: 3
Crazy 3: 2
Crazy 4: 4
Crazy 5: 7
Crazy 6: 5
Crazy 7: 3

Crazy 9: 2
Crazy 10: 7
Crazy 11: 1
Crazy 12: 2
Crazy 13: 2
Crazy 14: 4
Crazy 15: 3
Crazy 16: 2
Crazy 17: 3
Crazy 18: 2
Crazy 19: 2 (88% is possible with 1)

[LemSteven]

I forgot that Taxing 7 needs the glitch flag added.

Anyway, a few more results (a lot of these are from the WSCYLW thread)

Taxing 27: 6
Mayhem 1: 15
Mayhem 2: 6 (?) -- This is assuming the 6-builder solution from the WSCYLW thread doesn't need more than 6 blockers and/or bombers.
Mayhem 4: 2
Mayhem 5: 5
Mayhem 6: 6
Mayhem 7: 4
Mayhem 8: 3
Mayhem 9: 5
Mayhem 10: 5
Mayhem 11: 9
Mayhem 12: 3 (glitch)
Mayhem 13: 2

[ccexplore]

Mayhem 2: 6 (?) -- This is assuming the 6-builder solution from the WSCYLW thread doesn't need more than 6 blockers and/or bombers.

Confirmed--it uses 1 climber, 3 bombers, 4 blockers and 6 builders (and glitch with blocker to push crowd into a wall).  A replay was supposedly posted here, but I just noticed somehow the forum is no longer showing a download link anymore for it (same with many other older posts). I'll try to alert Adam or similar and see if that can be sorted out on his end.  If not, at least I can update all those posts of mine to reattach the missing replays.

[LemSteven]

Crazy 19: 2 (88% is possible with 1)

1 is now confirmed, as I was able to eke out 90%.

Although the fifth lemming can't be saved, he can still be put to good use.  With a perfectly timed bomber, he can take out a chunk of the ledge as he is falling, providing a low enough place to start the final basher.  The bomber must be timed perfectly, otherwise either he will take out some of the bridge or you won't get the proper terrain setup.

[Proxima]

Awesome! 

Also, as there are relatively few levels that need glitches for this challenge, I'd like to keep a record of the best results without glitches as well:

Fun 6: 2
Fun 15: 6
Fun 16: 6
Tricky 8: 9
Tricky 13: 5
Tricky 28: 2
Taxing 4: 10
Taxing 7: 6
Taxing 18: 6
Taxing 21: 3
Mayhem 1: 23
Mayhem 2: 8
Mayhem 12: 10
Mayhem 17: 6
Mayhem 23: 7
Mayhem 28: 13
Mayhem 29: 11
Tame 13: 3
Crazy 8: 4
Crazy 15: 4
Wild 9: 9
Wild 11: 6
Wild 19: 13
Wicked 1: 2
Wicked 3: 8
Wicked 10: 9
Wicked 13: 14
Wicked 14: 2
Wicked 15: 9
Wicked 20: 3
Havoc 6: 5
Havoc 11: 18
Havoc 13: 3
Havoc 15: 9
Havoc 17: 4

[namida]

I'll update to include these new results and non-glitch results later.

Although the fifth lemming can't be saved, he can still be put to good use.  With a perfectly timed bomber, he can take out a chunk of the ledge as he is falling, providing a low enough place to start the final basher.  The bomber must be timed perfectly, otherwise either he will take out some of the bridge or you won't get the proper terrain setup.

I used a similar logic in Cascade - make use of a lemming that would otherwise die. The difference being that in the optimal solution, this lemming DOES end up being saved, but the first worker dies in his place.

[ccexplore]

Completing Tame--Tame 13 is 2 (glitch) via sliding.

[ccexplore]

Crazy 15: 3

Clam's 2-builder solution (attachment still available in post) from WSCYLW also satisfies this challenge, so down to "2 glitch" for Crazy 15.

============

[edit: and 6 for Crazy 20, based on Clam's 5-builder WSCYLW solution.  Beginning cannot be done like that solution without using up too many bashers, so instead of using up 1 builder + 5 bashers there, we have 2 builders + 1 basher in this solution, keeping both skills' final usage count at 6.]

[ccexplore]

Some Taxing improvements:  Taxing 21 to "2 (glitch)" and Taxing 25 to 3.  I notice that with Taxing 25, not only do you end up using exactly 3 of each available skill type, but usage of each skill type is clustered to one area in the level per skill type, and the left-to-right order of these 3 areas matches the ordering for which the skill buttons are displayed!

[ccexplore]

More results:

Taxing 10: 4
Mayhem 17: 2 (glitch) via sliding
Crazy 8: 3 (glitch) via sliding
Wild 15: 2
Wild 17: 2

Wild 15 isn't all that spectacular, but it was harder to work out than I anticipated--other solutions I had initially would end up digging or bashing a little bit of steel in that area right before the exit and therefore would not quite qualify as glitch-free.  Wild 17 is nothing too special but is somewhat sensitive to precise positioning of blocker due to field alignment.

[namida]

Taxing 4: I've got very close with 3 per skill, but can't quite seem to group the lemmings together well enough to slide them up - my best is two lemmings short of the requirement. I'd say it can be done, though.

Wild 1: 2 per skill.
Wild 2: 5 per skill. Looks like it'd need 6 at first glance, but there's a trick you can use near the end to save one builder...
Wild 3: 6 per skill. You can do an across-the-top route if you like, but you still need 6 builders either way.
Wild 4: My best is 7, might be improvable with sliding.
Wild 5: 4 per skill. Take the low route. You can even block three of your bombers (but you'll need to time one, since you need a blocker at the bottom) - which is good, because two need to be pixel-precise and the other two still need to be pretty close to it.
Wild 6: 2 per skill. 1 per skill is possible to save 98% (with the last lemming dying, not being bombed), but the level requires 100%.

[Proxima]

Wild 7: 3
Wild 8: 10 (obviously)
Wild 9: 0 (nuke glitch) / 9 (glitch-free)
Wild 10: 3
Wild 11: 2 (steel glitches) / 6 (glitch-free)
Wild 13: 2
Wild 14: 2 (a nice challenge!)
Wild 16: 4
Wild 18: 5
Wild 19: 7 (ceiling route) / 13 (glitch-free)
Wild 20: 2

I've added my best glitch-free results for these and other levels to the post further up the page. (The result of 1 for Tricky 28 is glitchy, surely?)

[namida]

Tricky 28 result involves bombing away steel by being near it instead of actually on it (ie: not actually in the steel area). It doesn't involve sliding or steel cancelling or anything, though - the only other trick used was having a blocker turn a builder, which I don't think counts as a glitch. Do we usually count that one (the steel thing) as a glitch? If so, I'll add the tag.

If you do count that as a glitch, the glitch-free solution would be two, by doing it the same way but instead of bombing the steel, using an extra builder to get to the top of it.