Ratchet & Clank is a platform/adventure game in a similar vein to the 3D versions of the Rayman, Sonic, Mario, or other games. It involves the two protagonists Ratchet, a furry alien creature, and Clank, a nerdy little robot, going on a quest to find Captain Qwark and ultimately to help save the galaxy.

Ratchet & Clank includes many of the best features of previous similar games, but makes itself unique in a number of ways. Firstly each of the game's levels are huge sweeping vistas with extremely detailed buildings which are visible at all times (i.e. there is no distance fog). This means that a building on the horizon is not just a "backdrop"; in all likelihood Ratchet will be exploring it in a few moments time. Secondly, the game includes a number of sub-games, such as a space fight sequence and a number of turret shoot-outs which are akin to Missile Command in the first person.

The game has over twenty levels (planets) and includes as many real-time cut-scenes which tell the story. Also of note is that the story is non-linear, requiring the player to return to previous levels to complete objectives and to choose between multiple paths forward. There is also a respectable array of weapons, gadgets, and accessories to find or buy as the game progresses, which offer some unique gameplay features.

On a fine day on the planet Veldin, a furry Lombax named Ratchet is working on his spaceship when a robot crash lands near his home. Ratchet recovers the robot from the wreckage, naming him “Clank.” Clank shows Ratchet a recording of Chairman Drek of the Blarg race. In the recording, Drek explains that his home planet has become so polluted it is now uninhabitable. Drek’s solution is to build a new planet for his race by extracting areas from other planets! What’s worse is that Drek has developed a superweapon called the Deplanetizer which will destroy Veldin to make room for his new planet. Fearing that Drek will destroy everything in his path, Ratchet and Clank team up for their first explosive adventure to save the galaxy.