Thanks a lot for the replays and the feedback. I already feel bad for not replaying earlier.
Slow down, Walkers: I don't know how I missed this backroute.
Five do not survive: Backroute, that might not have been possible until the digger changed.
Stroll on the Lawn: Alternative solution, which is ok.
Minimalistic platforms: Great, then my efforts to make the level easy to execute paid off. Intended solution.
On the Toy Ship: Basically the intended solution. You simplified one small detail and traded it for some precision.
Cubism: This level is backroute-hell, and this is just one more of them...
Choir of the Mad: I already put so many fire traps there, and you still got around them. Backroute.
Minor Obstacles: Cool alternative solutions!
Chinese Lix: Yes, the intended solution is completely different. But I like your approach, even though I worry that allowing this leads to too much fiddling around. I am not yet sure, whether and how to fix this level.
Lament of Innocence: Known and acceptable alternative solution. You got the main ideas.
Three little Lix: Backroute.
Advanced Earth Cube: There are some good ideas in there, but the beginning is just backroutish.
On Magic Wings: Apart from the end, it resembles the intended solution. But that end has to be fixed.
Fall and Never Live: Yes, this is backrouty.
Dawn in Lixtown (and Night): Backroute.
A Day in Lixtown: This should be the solution for another version of Lixtown.
Ticket to Hell: Backroute, because the lemmings
should walk into the fire at the top. Not sure what I thought when putting terrain there...
The Shortcut: Not intended, but the level is bad anyway, so no big deal.