Crash Twinsanity

Crash Twinsanity differs from previous entries in the series through its free-roaming gameplay style; the player can explore the game's environments in all directions and travel seamlessly between levels. As opposed to the "hub room" format utilized by previous games, the player's progression through Twinsanity is influenced by the plot. Over the course of the game, the player controls three different characters: Crash Bandicoot, Doctor Neo Cortex (or both at the same time) and new character Nina Cortex; the controlled character alternates between particular levels. Crash is the primary player character and has the ability to jump into the air and land on enemy characters, spin in a tornado-like fashion to knock enemies off-screen, slide across the ground and perform a body slam to break certain objects.

Cortex is armed with a raygun and a limited amount of ammo, and Nina uses her mechanical arms to punch enemies and latch onto distant ledges. When Crash and Cortex are together, Crash can use Cortex to increase the range of his spin attack, use Cortex's head as a hammer to break certain objects, and hurl Cortex across gaps to activate switches. Two levels in the game incorporate a gameplay style named "HumiliSkate", which involves Crash riding Cortex as a makeshift snowboard, while two others are played in a style named "Doc Amok", which involves Crash clearing a path for a fleeing Cortex. Another gameplay style, named "RollerBrawl", involves the player steering Crash and Cortex through the level as they engage in a brawl.

Three years after his previous defeat by Crash, Doctor Neo Cortex returns to the Wumpa Islands to exact revenge on Crash. Cortex incapacitates Crash's sister, Coco, and impersonates her to lure Crash into a trap. After Crash's victory against Cortex and his Mecha-Bandicoot, Cortex and Crash are both sent plummeting down a hole and land in a cave. Enraged by his defeat, Cortex attacks Crash, and the pair engage in a prolonged fight across the cave.

Upon returning to the surface, Crash and Cortex encounter a pair of interdimensional parrots named the Evil Twins, who plan to destroy the Wumpa Islands and steal Cortex's brain. After Cortex pleads for Crash's help, he is spontaneously attacked by bees and finds himself captured by Papu Papu and his subordinate tribesmen after stumbling into their territory. Crash rescues Cortex from captivity and escapes a pursuing mob of tribesmen. Crash and Cortex have another encounter with the Evil Twins, who bring a deity statue to life to attack the pair.

Crash Twinsanity was developed by Traveller's Tales' Oxford division and published by Vivendi Universal Games. The game was originally titled Crash Bandicoot Evolution and featured a premise involving the Evil Twins stealing Crash's island from Earth and grafting it onto a giant planet made from pieces of others. The tone of the game was intended to be more serious than preceding entries in the series, with the term "edgy" being widely used among the development team. In response to the release of Insomniac Games' Ratchet & Clank, which featured an identical premise, Traveller's Tales abandoned Crash Bandicoot Evolution and restarted production with a focus on making the next Crash title as comedic as possible.

The new game went through several working subtitles, including Unlimited, Fully Fluxed and Twinsane. Eventually, VU Games gave Traveller's Tales one hour to choose the final title before the default selection of Unlimited. Concept artist Keith Webb came up with the title Crash Twinsanity with only five minutes to spare. The game was announced as Crash Bandicoot: Unlimited on March 26, 2004, with Crash Twinsanity originally intended as the game's American title.

Crash Twinsanity received mixed reviews from critics upon release. The open-world setting was welcomed as an improvement over the "claustrophobic" level design of previous games, and the various gameplay styles were commended as clever and well-implemented; James B. Pringle of IGN compared the 'ingenious' Doc Amok levels to Lemmings, and Louis Bedigian of GameZone considered the RollerBrawl sequence to be the game's best. However, the platforming sections were considered formulaic and tired.

The gameplay aspect of controlling Crash and Cortex in tandem drew comparisons to Jak and Daxter and Whiplash, while the RollerBrawl segment was widely compared to Super Monkey Ball. The character Nina Cortex was positively received by critics, some of whom compared her extending robotic arms to Bionic Commando. The game's camera was widely criticised as dodgy and uncooperative, and the controls were deemed sluggish. Kristan Reed of Eurogamer and GR Chimp of GameRevolution respectively derided the checkpoint/autosave system as faulty and spaced too far apart.