The fact that you have to manage your ressources and shoot pass through the ennemy add a nice strategy touch that simply shoot and kill.
Fun, a bit repetitive but it's hard to add too much gameplay in a jam haha. I had the idea of a non movable object and shooting in rotation and find it too simple and went a bit away, your little touch is a good idea!
I didn't have any problem with spacebar or zoom! (Google chrome here)