Paper Mario is set in the Mushroom Kingdom as the protagonist Mario tries to rescue Princess Peach from Bowser. To do so, he must locate seven "Star Spirits" to negate the effects of the captured Star Rod, which grants invincibility to Bowser. The player controls Mario and a number of partners to solve puzzles in the game's overworld and defeat enemies in a turn-based battle system. The battles are unique in that the player can influence the effectiveness of attacks by performing required controller inputs known as action commands. Peach is also playable in particular parts of the game to complete stealth-based objectives.
Paper Mario is the first installment for the Paper Mario series and is the predecessor to the GameCube game Paper Mario: The Thousand-Year Door. The game received a positive reaction from the media, attaining an aggregate score of 88% from Game Rankings and 93% from Metacritic. It was rated the 63rd best game made on a Nintendo system in Nintendo Powers "Top 200 Games" list in 2006.
Paper Mario combines traditional role-playing game (RPG) elements with concepts and features from the Mario series. The player controls Mario for the majority of the game, who can jump and use his hammer to overcome physical obstacles placed in the game's overworld. Many of the game's puzzles and boundaries are based upon the abilities of Mario's partners, who each have a specialised skill required for progression in the game. The player accumulates partners as they advance into different locations; only one partner can accompany Mario in the overworld, although the player can interchange between them at any time. These characters also assist Mario in the game's turn-based battles, where damage inflicted against them results in temporary paralysis as the characters do not have individual HP statistics. Attacks in the game are similar to those in traditional RPGs, although the player can influence the power of a move when attacking or defending by timing a button-press accurately or performing some other action command as required. Mario and his partners have a finite capacity to perform special moves, with each of these consuming a particular number of flower points (FP) when performed. Such statistics can be increased by earning experience points in combat to level up. There is also an on-screen gauge to display Star Energy, which is required to perform another type of move that accumulate in number as the player advances through the game. The player can locate hidden battle upgrades in the game's overworld, which promotes one partner character to a new rank at a time.
Progression through Paper Mario depends upon interaction with the game's non-player characters (NPCs), who will often offer clues or detail the next event in the storyline. As in other RPG games, the player can find or purchase items from NPCs to help in and outside of combat. Badges can also be obtained that yield bonuses ranging from added moves to gradual health restoration during combat; each consumes a set number of Badge Points (BP), meaning Mario can only equip a limited number of badges at a time. Princess Peach is playable at particular points in the game as a recurring side quest. The objectives and actions of each transition to Peach vary, although most are stealth-based.
The game is set in Mushroom Kingdom, beginning as a party is being held in Peach's Castle. After Bowser's invasion, the Castle becomes attached to Bowser's Fortress, which serves as the location for playable side quests of the kidnapped Peach. In the main quest, Mario tries to retrieve all of the Star Spirits on land, where most of the locations are linked to the central Toad Town, which acts as the game's hub area. The story's main conflict arises when Bowser invades Star Haven, the residence for the seven Star Spirits, and steals the Star Rod.
Mario allies with eight partners in total, each of whom represents a different type of enemy from the Mario series. There is Goombario the Goomba; Kooper the Koopa; Bombette the Bob-omb; Parakarry the Paratroopa; Lady Bow the Boo; Watt the L'il Sparky; Sushie the Cheep-Cheep, and Lakilester the Lakitu. Near the end of the game, Mario recounts his tale to Luigi, who had remained at home while Mario went on the adventure.
Critics lauded the game's blend of RPG and platforming aspects. GameSpot noted the "exciting and somewhat strategic" battle system, which requires the player exploit the enemies' weak points. The "refreshing" action command features was praised in particular for adding originality to a battle formula that was present in many games of the same genre. Despite this, enemy design itself was bemoaned for being "corny and generic", with notable exceptions to some of the Paper Marios original boss characters. Eurogamer noted how "Of the various characters you meet, none is of less import than any other", welcoming the partner characters and their relating puzzles. GameSpot praised the game's use of humour and side quests, with references to the control of Peach in particular.
The reaction to the game's visuals was generally positive. IGN noted some paper-based visual effects such as when Mario folds in a bed to sleep, but complained about character zoom-ins, which revealed "a pixelated mass of colors". Although reviewers claimed that the novel graphical style was initially confusing, most welcomed the style eventually, with GameSpot claiming that it was "extremely well done". The audio was also mainly praised, although reviewers criticised the lack of voice acting and character-specific sound effects. RPGFan were particularly critical of the game's "generic filler music", despite enjoying use of multiple songs simultaneously. The game was also well received in general upon release for the Virtual Console, with IGN's Lucas M. Thomas stating "it's held up very well even placed into context against its GameCube and Wii era sequels, and it's an RPG for goodness sakes". Paper Mario proved popular on the Virtual Console, reaching a high of 'Second most downloaded game' in the US in August 2007.
Paper Mario was the top selling game in Japan on its week of its release, selling more than 276,000 copies. It was also the eighth best selling game from January to June 2001 in the US. It was voted one of the top 100 games of all time by Electronic Gaming Monthly. Paper Mario was rated the 63rd best game made on a Nintendo system in Nintendo Powers "Top 200 Games" list, and the 13th greatest Nintendo 64 game of all time by the same magazine.