Smurf's Rescue in Gargamel's Castle? The 7th best cheat code ever? Yeah, just wait; the news actually gets worse. It's technically not even a cheat code. It's a secret. But it's one of the ballsiest secrets ever programmed into a videogame; especially when you consider we're talking about a Smurf's game.
North American box art for the original Metroid. The top left corner shows the words "Password Pak", referring to the password system. The original Metroid released in the US and Europe is the only game in the series to use passcodes. The original version released in Japan had save slots. However, the western versions did not have these slots, instead utilizing a passcode system for restarting. When the player died in the game, they would be given a code to use. After they entered the code, they would be brought back to the starting elevator of the area they were currently in with all of the upgrades acquired in the preceding play.