Four Wheel Drive Car - Compact Addition

Four Wheel Drive Car V3 was the best in young humanoid's four wheel drive car series, but young humanoid decided to add a special addition to the series. Taking some inspiration from a website, he made a very compact, four wheel drive, two wheel steering robot. He made a remote control for it, using a second NXT and an Acceleration/Tilt sensor. The car would move in the direction that the control was tilted. This was all fine, but young humanoid decided to rebuild the vehicle for another online competition. Unfortunately it was weaker than before, he must have built it wrong or left out some part. Here it is:

Smal Rover 2

Well, the same thing happened to Small Halftrack happened to Small Rover as well.....young humanoid rebuilt it, but made it more compact by concealing the wires and using a light sensor instead of a touch sensor for object detection.