Swapping Lasers HTML

This is my first full/fullish game. The basis of it is just a 2d game where you control 2 characters and have to move them while using a laser to kill the enemies.

PLEASE give me feedback, like I said, its my first real game so I need feedback.

Controlls: 

Move: w/a/s/d

Laser: Hold spacebar

Swap Character: e