Those are some wacky moves on the enemies and gun, uh. Its a cool idea and I'm glad you finished it.
Just some feedback to improve on future games: 1. the player can't really reach the space bar, mouse and arrows at the same time, either change to WASD or put arrow up to jump; 2. Just let the player fire while holding down the button if there isn't something like a charge shot. 3. Do more testing and polishing, the gun doesn't always fire from the right place and it's very hard to actually keep the enemies away