Factual error: When the aliens first take over the Thunder Road, Wolfgang says that he will reverse the "x-axis diode" to make the computer think they are traveling in the opposite direction. However the outside view shows them moving up and forward at a steep angle, ie moving up on the Z axis and forward on the X axis. If they X axis diode was reversed then the Thunder Road would still be ascending at the same rate, simply in the opposite direction (basically changing from moving forwards and climbing to moving backwards and climbing) . To make them descend, he would have to reverse movement on the Z axis. Considering it's shown on screen that Wolfgang designed the interface to make the sphere move on XYZ coordinates, he would know this.
Add timeGrumpy Scot