Got to 200!
I enjoyed the gameplay with the health bar also serving as ammo for heavy attacks and overcharged batteries leading to a boost in move speed. I also felt that there was great player feedback, with a satisfying damage and 'kill' sound when attacking enemies. Additionally, just a personal opinion, though the walking sound was a bit wacky, I really liked it, and felt it complimented the robot.
At a point, the difficulty sort of plateaued, I feel one solution would be to increase battery decay as score/time increase, or like Dimensions2003 said, add more enemies.
Fun game!