I like the concept behind this a lot; having the AI control one part of the robot and the player the other. Very cool. And the gameplay loop was certainly fun -- I particularly enjoyed the laser. The shotgun and machine gun seemed too difficult to properly use (I guess you need to have the enemy on one end and then rotate before it shoots or something?).
It's been noted a lot below, so I'll not mention the voice lines, but one other thing that tripped me up a bit was the initial appearance of the robot in each room. It always took me a few moments to figure out where I was, which was problematic considering that all the enemies immediately know where I am, and some rooms requires you to react quickly. Maybe having a the player contrast a bit more with the background would have helped, or centering the camera on them?
I also would have liked to know what exactly the upgrades do. I can upgrade them, but what does it upgrade? Damage? Fire rate? Something else? A short description might have aided there.
Overall, I quite liked this. It's a very solid gameplay loop and a nice concept.