Quite a few problems with this game, I'll name a few:
A: Can't control how high you jump, really cuts down on flexibility for the player, which is annoying.
B: Cannon thing's shot traveled to the end of the screen instead of dying out after a certain range, adding a layer of unnecessary difficulty.
C: Sloppy controls, hard to precisely control character.
D: NO CHECKPOINTS: This combined with the precison needed to finish a course as well as the sloppy controls for the player is an instant turn off for any player.
My advice is to polish this stuff as well as testing your game out by playing it ore submitting it.