Developer: Nintendo EAD
Released: 2001, GameCube
Luigi's Mansion was one of the very first video games to be released for the Nintendo GameCube, that involves Luigi going through rooms in a mansion sucking up ghosts with a vacuum cleaner. It was different from the other Super Mario games, mostly because it focused on Luigi and had a clever combat system that would later be the sub-standard for the character itself.
But that's not all; the game has a lot of interesting early content featuring unused graphics, animations and a lot of leftovers from during development of the game. There's also a handful of other differences such as a completely different challenge mode in the European version.