Paper Mario: The Thousand-Year Door is an RPG made by Nintendo and is the second game in the Paper Mario series following Paper Mario for the Nintendo 64. It incorporates a world made of paper and turn-based battles, much like its predecessor.
In it, Peach asks Mario to help her find a treasure hidden in Rogueport. When he arrives, she is missing as usual, and he must collect seven Crystal Stars to save her and open the Thousand-Year Door to collect the treasure.
While overall a well-programmed game, there are a few "unintended features" that allow one to skip large parts of the game.