I really missing Sound, just a pew Sound for the shooting would be already perfect.
The Jump of the Character is funny and makes a lot of fun just jumping around like an idiot xD
To make the Game easier beatable you might wanna consider shooting in the Air, because at the moment its hard to get by some of the areas especial when those Enemies are standing on the Stair and not moving at all, you cant approach them you will die always as a player.
Solid Work, keep going!