About halfway through Psychonauts, you're faced with this dilemma: How to kill the giant lungfish with the vacuum breath? Some trial and error determines that smashing open boxes of tacks while it inhales does the trick. Still not dead? Try closing an open clamshell on its lip and pounding away for a stretch. More signs of life? Slap a psycho-portal onto its cranium, climb inside, and enter the world of Lungfishopolis, a sprawling cityscape in which you're swatting down planes and stepping on tanks like King Kong. Such surreal encounters are commonplace in this wildly inventive game, which bounces from one brain to the next in a grand psychic quest, each percolating with its own bizarre obsessions, such as the disturbed whisperings of a conspiracy theorist or a party queen's floating discotheque. The cheerfully bright, crooked spaces look a little like Pee-wee's Playhouse on powerful hallucinogens, and Psychonauts keeps upping the dosage as it goes along.

A wittier take on Nickelodeon-style genre standards like the Jak And Daxter and Ratchet & Clank series, Psychonauts takes place at the Whispering Rock Psychic Summer Camp, a recruitment facility where special kids hone their psychic abilities. You play star student "Raz," (short for Razputin) a spirited cadet called into action when an evildoer steals the brains of all your classmates and teachers, save for a wizened old-timer who appears whenever you lure him with a piece of bacon. Using an accumulation of special mental powers—including telekinesis, clairvoyance, and levitation, among others—you try to find and rescue the stolen brains and liberate minds clogged by emotional baggage, cobwebs, and numerous extrasensory bugaboos. Beautifully paced in their train-as-you-go chronology, the missions get progressively harder until the big showdown at an asylum, where all your mental faculties are tested inside the heads of madmen.

Beyond the gameplay: The excitable kid heroes in most platform games are usually annoyingly precocious, like Jake Lloyd in The Phantom Menace, but Psychonauts is sprinkled with oddball dialogue, especially along the margins. In a suburban neighborhood laid out like an Escher painting, for example, workers drone lines like "Being on the road crew is arduous but rewarding," and "I wear sunscreen while trimming hedges to prevent melanoma from developing on my skin."


Worth playing for: Most games establish their worlds' look and scope right away, but Psychonauts constantly expands and reinvents itself with each new mental landscape. It's always worth pressing on just to see what the next one looks like.

Frustration sets in when: All platform games require the collection of various artifacts and doodads, but Psychonauts goes more than a little overboard. Throughout the game, you have to pick up arrowheads (for currency), astral layers, figments, cobwebs, baggage, memories, merit badges, playing cards, and items for a bonus scavenger hunt. Raz has enough things to worry about without them.

Final judgment: Psychonauts was four years in the making, and clearly not a minute was wasted.