This is a pretty fun game but I noticed in that the enemies some times just walk righy over the edges instead of falling. Like in the fox level they go just straight across the edge to the other side withough falling.
You might also want to try setting it where after a game over you go to the character select screen. I liked the intro but seeing it everytime I died kinda got a little annoying.
The game was really fun to play and I hope you keep up the good work :)