When you have understand what you suppose to do, the gameplay idea is pretty fun. The interpretation of "you are the weapon" is very interesting (like the ammo = health points), and the UI is cool.
But there really misses a visual feedback for the damages, and a little music ;)
And maybe some explanations, who tell us why a gun make backflips, in space, while shooting on targets with arms who shoots .. i don't know ... hands? (That was funny xD).
So, a pretty cool concept who can be more pulled up!