Uh, thats a nice game, that deserves MUCH more levels!
It would be nice, if the players could have different colors (or more features ike the mouth) to distinguish them during play.
Music and graphics are really fine. Well made Game! Congrats!
If you are adding more levels, you might also want to add other obstacles, or triggers to open doors, etc. Maybe even something, that both players have to do at the same time