Hyper Rally is a rally race seen from behind the car, down a road drawn in fake 3D. You drive one car through twelve stages, each with its own scenery: day, tunnel, snow, a desert where three pyramids rise as you near the end, a storm that throws lightning, and two run at night under a field of scrolling stars.
Under the road sits a dashboard the code keeps up to date every frame:
The wheel comes from 0x6643, the accelerator and brake from 0x6940. The car is six sprites (template at 0x66E2) that 0x65FA slides sideways as you steer. Rival cars come up the road; hitting one halves your speed (0x7F89, which walks the same three opponent records).
The stage number lives in 0xE060 and runs from 1 to twelve. Reaching the end of a stage's track advances it; at stage thirteen the rally is over. Each stage also loads its own parameter into 0xE061, and that is what decides whether the car skids, whether the sky carries stars, and whether lightning falls.