This is a very nice and fun puzzle game that could go on to be much bigger if you developed it futher. The sound effects are quiet nice and the simplistic style of the game is very nice.
The main problem that I have is that your characters can go past the checkmark point and of into the void. Its pretty fun when you flip the game when this occurs .
This could definately be put on an app store and do well due to its simple yet satisfying gameplay that can get people hooked for hours. Good job!