Traveller's Tales
Jon Burton, founder of Traveler's Tale, hid glitches and crashes in games to pass Sega's certification process. Whenever theses glitches or crashes would happen in games like Sonic 3D, Toy Story and Mickey Mania, the player would be sent to a level select screen or a secret level. This explains why smacking a cartridge of Sonic 3D will sometimes trigger a level select screen.
Contributed by Kakariko Kid