Overall I wonder about the many (ofter rather harsh) time limits. Do you really feel that the levels get more interesting with all these time limits?
Back and Forth: VERY similar to finlay's
Fiery Depth in finpack01.dat. Both levels are very good though.
Son of a birch!: Easy level, except for the combination of frenzy gimmick and skill assignments on different parts of the level nearly at the same time...
Tip of the Blade: The time limit is
very annoying here. Otherwise a good level, that allows for a solution saving 21/20.
Special Beam Cannon: HIDDEN TRAP
! Otherwise an interesting level.
Clockwork Grey: Good level. The one-way-field extends into the terrain above. This is slightly annoying if one bashes away parts of this terrain and instead of continuing ahead, the worker lemmings gets trapped!
Coarse, grain, ...: Just build over any obstacle and you will be fine...
Up a creek...: Most likely a backroute.
Harder, Better, ...: I have one builder spare
. Good level, though I wonder at the use of some parts of the terrain.
Try to keep him digging: I tried, but failed
. Feels like a backroute.
Lemming Train: Excellent level
.
Into the Builderless: Not really a fan of this one. namida has more interesting no-builder levels in his LemPlus series and the level is not really beautiful.
Lemming climb no stairs: Nice interplay between climber/cloner/bomber.
Quarantine: Far too straight-forward builder level for my taste.
Quick Piramid: Another Frenzy gimmick level...
Mobi, did you shrink the levels?: Excellent design and puzzle
.
Slap me... Not my favourite.