Hidden secrets, developer jokes, and undocumented features
A secret room containing the message "Created by Warren Robinett" — the first Easter egg in video game history.
Entering Up, Up, Down, Down, Left, Right, Left, Right, B, A at the title screen grants the player a full set of power-ups — the origin of the most famous cheat code in gaming history.
Entering ABACABB on the Code of Honor screen re-enables all blood and fatalities that were censored from the Genesis port by default.
A hidden debug mode that lets the player fly freely through levels, spawn any in-game object, and view the game's internal ring counter and position data.
A glitched level accessible through a specific wall-clipping trick that sends the player to a corrupted "World -1," an infinite underwater loop that cannot be completed.
A hidden room in Episode 1, Map 4 containing the digitised faces of the id Software development team mounted on the walls like trophies.
A hidden cheat that replaces all bullet-impact blood splatter with large colourful paint blobs, giving the game a slapstick visual aesthetic wildly at odds with its spy-thriller tone.
The final boss of Quake is revealed to be a hidden idol containing a digitised, impaled head of id Software co-founder John Romero.
A hidden screen displaying personal messages and credits from the Capcom development team, accessible through a specific button sequence at the title screen.
Multiple hidden rooms and a secret world accessible through obscure warp barrels and out-of-bounds movement, including the completely optional Banana Bird Caverns containing collectibles unknown to most players.
A deliberately cursed in-game painting of a sad clown that, when hung in a Sim's home, causes the household's mood to deteriorate and summons a manifestation of the clown himself.
By equipping the W-Item materia and cancelling out of the second item selection during battle, the game duplicates the first selected item — allowing infinite copies of rare consumables like Megalixirs.
A password that starts the player near the end of the game with most power-ups collected, and crucially, displays Samus Aran as a woman in a swimsuit rather than in her Power Suit — one of the first times a major game protagonist was revealed to be female.
EarthBound contains hidden code that detects pirated copies of the game and punishes players with escalating difficulty before deleting all save data at the final boss.
NBA Jam contains secret playable characters including Bill Clinton, Al Gore, Prince Charles, and various Midway staff members, unlocked through specific initials and button combinations at the player entry screen.