Hello!
first: I'm Baggers, a gamer since AppleIIGS ^^ (yeah, the old apple computers before Macs) and Apple2GS has the lemming game!
But I going to you, because a little french independant studio just released a lemming-like game!
http://www.zombienightterror.com/https://www.youtube.com/watch?v=XAz-xc-ndl8Seems legits, no?
OK, it look like more action than lemmings on the trailers, but I have tried it and trust me: it's lemming and puzzles.
I see you have a "level design" section. I'm curious if some things can applies... Unfortunately, the level-editor isn't out at this time. (In a few mounth they say)