Cool use of the limitation! Also think it's interesting you refer to the robot being the main character in the submission info - so, really, we are the enemy?
I did find it very difficult to get past, uhm... the... 90% mark? Might simply be bad at the game, but I feel like being defeated in one hit is a bit too punishing, which made me feel a little less inclined to keep on playing after being defeated.
Aside from that, I do like the game's visuals! They're pretty and you can clearly distinguish who/what you play as from the background, as well as where the bullets are!