I only have one small criticism.
I didn't try it on multiplayer, and when on single player the AI version seems to always get a perfect shot of way quicker than I could manage to work out the best angle. Would it be better to have a range the AI would fire within that may fall out of the player's hitbox to give the player a slightly better chance.
You could also have the AI pick between three targets, one being the right one and the two others miss shots, giving the player a fighting chance.
However I do understand that the point was to only have one shot just thinking more for taking the game forward if you wanted to remove the single shot you could potentially give the player and AI limited ammo instead.
See just a small criticism XD
but seriously, I really did enjoy it don't let the above make you think otherwise, it was just difficult for me to play at first until I managed to adapt.