Apart from the batteries running down rather quickly and the wheel spin...
I noticed when driving the Robot I had to keep adding a little more power
to the left hand side of the Bot (as viewed from the rear) via the controller
ie :slightly turning right to keep the Robot on a straight track.
The gearing for the motors is identical and so are the motors and wheels,
I'm thinking the right hand side of the Robot could be getting a little bit more
traction than the left side- retro fitting bike tyres or similar could resolve this, so
it might be better to remedy this before altering any trim on the controller.

We may turn our attention to the weapon this weekend while we ponder
the best way to improve the traction and battery longivity