Paper Mario: The Thousand-Year Door - Reception

Paper Mario: The Thousand-Year Door was generally well received by critics. Critics praised the game's plot in particular, and GameSpot's Greg Kasavin stated that "each one provides a thrill of discovery" when referring to the game's individual chapters. Similarly, Eurogamer welcomed the whimsical storyline in comparison to traditional role-playing games, commenting that " something closer to Finding Nemo than Final Fantasy, which is very much a compliment." The game's characters were also well received, with reviewers complimenting the use of NPCs and text. Despite this, some reviewers did complain that the story developed slowly in the beginning stages of the game. Eurogamer also rated the high level of text as "the only major stumbling block" of the game.

One of The Thousand-Year Door's main features, the use of a paper-based universe, was welcomed by reviewers. When referring to the paper theme, 1UP commented that "It's a cohesive, clever approach that turns the game's visual style into more than just a look". Critics also commented extensively on the game's battle system, which deviated from traditional RPGs. GameSpy praised the use of timing in the battle system, stating that "these twitch elements were designed to be fun and engaging, and they succeed wonderfully at this". Reviewers also praised the concept of having an audience to reward or berate Mario during battle.

The game's visuals received a mixed response from critics. GameSpot enjoyed the game's presentation, writing that "it exhibits a level of visual artistry and technical prowess matched or exceeded by few other GameCube games". Conversely, other reviewers complained that the graphics were not much of a visual upgrade from its predecessor, Paper Mario. For the game's use of audio, IGN declared it "game music at its purest", but proceeded to question the absence of voice acting in the text based game. RPGamer commented that the music "for the most part is done very well", but that the perceived repetitive battle music was "one of the biggest flaws" of the game. The game won "Role Playing Game of the Year" at the 2005 Interactive Achievement Awards. The game was ranked 56th in Official Nintendo Magazine's "100 Greatest Nintendo Games" feature.

In its first week of release in Japan, The Thousand-Year Door was the best-selling game, with approximately 159,000 units sold. It proceeded to sell 409,000 units in the country, and 1.23 million copies in North America. The game has since been included in the Player's Choice line.