Upon starting the game, the player takes control of Sulley, who is introduced to Thaddeus Bile, one of Monsters, Inc.'s new recruits, by Henry J. Waternoose III. The player is tasked with finding and obtaining Bile's manual and key card, which are essential to his training. The player then must ride the mail train to reach Boo, while avoiding being stopped by CDA agents. However, Boo soon manages to escape again, forcing Sulley to race through the rooftops of Monstropolis buildings, while avoiding being spotted by the CDA helicopter. Soon after getting ahold of Boo once more, Sulley must search in his apartment building for materials to create a disguise for Boo, so as to hide her from other employees at Monsters, Inc.
Once at Monsters, Inc., Boo escapes from Sulley's hands once again, and ends up at the garbage disposal, a very dangerous place. As such, Sulley must chase Boo, while avoiding other monsters that look similar to Boo's disguise. Sulley later must go to the Himalayas, and reach the village. Upon Sulley's return to Monsters, Inc., he must explore the huge library of closet doors, while avoiding falls. In the final level of the game, Sulley must shut down the power supply by scaring the switches, and saving Boo from the hands of the evil Mr. Waternoose.
The Scare Floor (get Thaddeus' manual and key card)
The Mailroom (Ride the mail train and get to Boo while avoiding the CDA)
Main Street (Traverse through the rooftops of Monstropolis while trying to find Boo and avoid the CDA Helicopter)
Sulley's Apartment (Run through Sulley's apartment building and find materials for Boo's costume)
Garbage Disposal (Chase Boo through the garbage disposal and don't get tricked by the monsters that look like her!)
Himalayas (Go through the Himalayas to get to the village)
Door Vault (Explore the giant library of all the closet doors and don't fall!)
Showdown (Shut down the power supply by scaring the switches and save Boo from Mr. Waternoose)
Tot Bot Scare Fair: Scare as many simulation bots as you can before they wake up!
Canister Catastrophe: Collect the canisters as they are going through the conveyor belt before you lose!
Closet Chaos: Keep the balls from landing in the center and spin them away with your tail. Every time a ball pops, one health point (tooth) is reduced.
Furry Scurry: Play Pac-Man, with a Monsters, Inc. twist! Collect the red scare tokens while the CDA try to catch you! Grab the canisters to get rid of the CDA agents for a short period of time.
Yeti Says: Play a "Simon Says" type of game with the Yeti. Repeat the rhythm he does correctly or lose a point!