Some developer notes point to hidden "Debug Menus"—on-screen interfaces that display real-time data like frame rates, collision boxes, or entity counts.
Historically, developers created these "cheats" because it was impractical to play through an entire game just to test a specific mechanic or late-game level.
Developers used these shortcuts to isolate bugs in specific environments without needing to meet difficult gameplay requirements. Key Characteristics
Originally a developer tool for Gradius on the NES because the game was too difficult for the creator to finish while testing.