I mean, that when the play opens a game he usually expects that space button will make player jump, "a" and "d" buttons will make player go left and right and left click (on mouse) are going to make player's weapon shoot. It is not present in EVERY single game, but it is quite common. In your game player shoots with space which felt very weird for me.
Also collisions are little buggy - if you jump at the right side of block and go right in the same time the player starts shaking.