It's not bad, but there are some parts where it becomes ridiculously unfair; either because it's difficult to guess what you have to do or because of the nature of the challenge itself.
There is a bug with the green snails; if you push them too far in a corner, they will get out of it, I don't know if I'm explaining myself well.
The gameplay is quite slippery (maybe due to the fact that it's a snail?) but the physics are pretty good. The music and the graphics are not bad.
I liked it, but it could have been better.
Sorry for my bad English.