Thanks for your solutions! The backroutes weren't quite as many as expected.
'Follow Me' is simply flawed. I've had done backroute fixing too many times, but it's just too open-ended to look over. I think I'll design a different level using the same trick sometime.
I really like 'Trading and Cooperating' actually, but it seems I'll never manage to weed out the backroutes there. Would you mind to retry imagining a steel wall where the one way arrows are as of now?
'Upset Lemmings' was actually unexpected, I didn't think that timing was possible. I suppose with a higher first pillar it wouldn't be.
Only minor variations on the other levels (and I've forgot the original solution to 'Increasing step heigths', I even wrote a solution for it once, but that got lost. I think it used a somewhat complex compression and dynamic steps).
Anyway, I hope my levels have been somewhat playable, I feared the amount of precision and timing might make them somewhat annoying to play.
I'm somewhat suprised that you liked 'More no-builder problems' best, I found it mostly just using standard procedures already required in 'crossing stairs' (my solution slightly differs from yours, but it's still similar).
I haven't played Lemmings for quite some time, but checking my recordings folder tells me that I've got four of your latest pack left to solve (not counting the XMas pack).
Builders' Cracks: There only seems to be one way to do it, but I need to do some optimisation on the builders.
Dropout: The timing seems insane in this one. Got close a couple of times, but never managed it.
From the brink: this one is somewhat stunning me.
The Floodgates Open: Seems like an interesting and complex puzzle.
Here is SST's first pack:
http://207.58.177.175/~geoo89/lemmings/twigpak1.dat