"One of the most addictive and entertaining physics-based driving games ever created! And it's free! Meet Sonic, the young and ambitious uphill motocross racer. He is about to embark on a journey that takes him to places where he has never raced before. From Ragnarok to a nuclear plant, every location is a race track for Bill. With little regard for the laws of physics, Sonic will not rest until he conquers the highest hills on the moon."
In terms of the laws of physics...