The concept is pretty good and the puzzles are well designed. The controls aren't great though. It takes too long to move one tile and you have to keep pressing keys to move instead of holding them down to keep moving in a direction. This gets especially frustrating when you make a mistake that forces you to reset the level, like pushing a crate against a wall. I also think the music shouldn't restart when you go to a new level.
Good work though, there is surely potential for a good puzzle game from this idea :D