[BJC]

I would be very concerned about the giant structure that sticks out the back of the robot at bumper level. This game will involve a lot of full speed robot collisions.

A good frame of reference to have on stuff that sticks out of the robot is "if I kicked that part as hard as I could, would it break?"

That back structure appears to be mandatory for your design to work properly. I would recommend making it out of 1x2 rectangular box extrusion or at the very least triangulating it with some diagonal members.

Good Luck!
, Bryan