Excitebike

Excitebike was visionary: a 1984 NES launch title with a full track editor. You could create custom motocross circuits with ramps, holes and obstacles, then race them. Gameplay balanced speed with engine overheating. Miyamoto designed it as a Famicom capabilities showcase. The editor couldn't save creations (no battery in the cartridge), but the 'user-generated content' concept was decades ahead.