Disney's Kim Possible: What's the Switch? is the fifth video game of the Kim Possible series. It is the first Kim Possible game to appear on a home console, as all the other Kim Possible games were designed for hand-held systems.
Kim Possible and Ron Stoppable arrive at Monkey Fist's castle to obtain a Monkey Idol before Dr. Drakken and Shego can get it first. However, when the two teams fight over the Idol, the power of the Idol affects Ron and Drakken, causing their minds to switch with each other's bodies. Before Kim or Shego can respond, Professor Dementor appears and steals the Idol himself.
Realizing that she needs the Idol to switch Ron and Drakken back to normal, Kim takes off in hot pursuit of Dementor. Shego, however, is also hot on his trail as the two fight through the streets and rooftops of London. In Big Ben, the two meet up again and almost begin fighting each other as Dementor escapes in his air carrier, but a call from Wade eventually have the two form an uneasy alliance to get the idol back, Kim giving Shego Ron's Kimmunicator that was given to him in the events of Team Possible. Although they succeed in getting into Dementor's air carrier, Shego leaves Kim behind and bails out as it almost crashes in his Alaskan lair, resulting in Kim being forced to stoaway on one of Dementor's trains while Shego makes her way through abandoned mines near the tracks. Wade still makes contact with Shego despite this, however, giving her advice on how to get to Dementor's lair.
Within Dementor's Alaskan Lair, it is revealed that Dementor and Monkey Fist were working together, Monkey Fist capturing Shego and escaping the lair with her while Kim disables Dementor's new Siesmic Disinhibitor (a doomsday device). Monkey Fist's double-crossing and stealing of his "greatest invention" causes Dementor to end the villainous alliance, but Kim finds her way on board the frieghter Monkey Fist is on. Although she fails to keep the ship from crashing in Tokyo harbor, she does manage to rescue Shego from captivity.
In Tokyo, Monkey Fist unveils his "Mecha Monkey", powered by the Idol he had stolen, which goes on a rampage through Tokyo after splitting in half. Despite legions of robotic monkey ninjas and several wrong turns, Kim and Shego manage to get onto the Mecha Monkey and disable it, escaping with the Idol as it self-destructs (Monkey Fist being caught in the aftermath). Drakken and Ron have their brains switched back and Kim thanks Shego for the "fun and games".
The gameplay in What's the Switch? follows the same sidescrolling format as the predecessors. Kim is playable in all levels, while Shego is in all but one and Rufus appears in a select few levels. Differing from previous games is the use of a 3D enviornment, which is cartoony like the show. Kim, Shego, and Rufus are alternated between on levels, though Kim remains the sole character of the level Monkey Sea... and is the only character used in bonus missions.
Along the path of each level, the player has the option of collecting two kinds of tokens; Kimmunicator and Club Banana. Kimmunicator tokens unlock bonus content, and gathering all tokens on every level of the game unlocks Kim's mission outfit for Shego as an alternative outfit. Club Banana tokens only unlock outfits, each level having three tokens. The outfits are not unlocked linearly, each level has three tokens and if all three are collected the approperiate outfit is unlocked. Green and Red health tokens also drop to replenish both character's 5-hit health bar, and orange KP tokens grant extra lives.
Bonus missions take place in a 3D simulator created out of square blocks of varying types, and there are six of these missions. Access to these missions is gained by finding the secret mission cubes in certain levels. Not all levels have these, and they are often dangerous to reach, such as being found over a reservoir of toxic fuel.
The game is also noted for having improved henchmen AI and henchmen having greater range than either Kim or Shego and much shorter times between attacks, giving players a greater challenge then enemies in the previous games. They are also of several types of henchmen besides the differentiation between Dementor and Monkey Fist's. Heavy henchmen are armored and must be left vulnerable by either an uppercut or a flying kick, jetpack henchmen can charge and are invulnerable while doing so, ranged henchmen hurl explosives, and stealth henchmen render themselves invisible until revealled by Kim's EMS. Dementor uses his regular henchmen while Monkey Fist has robotic monkey ninjas designed by Dementor. Ghost monkeys and unique model 'mini' mecha monkeys also appear in the first and last levels of the game, respectively.
There is also multiplayer modes for those looking to play with a friend.
Kim and Shego both unlock outfits, much like Kim was able to in the previous game released, Kimmunicator. They are changed at specific points in the levels, denoted by an orange light with a non-rotating Club Banana token hanging above. These outfits are strictly cosmetic and do not convey any bonus to the characters. They are consistent through cutscenes, but are reset when the game exists to the main menu. They can only be changed in the levels themselves.
Kim starts with her mission outfit, but can unlock her Beuno Nacho work outfit (from Beuno Nacho), her snow gear (Downhill), an armored mission outfit (A Sitch in Time), her battle suit (So the Drama), the Centurion Project (October 31st), Sheela (Bad Boy), and Shego's outfit (The Twin Factor).
Shego begins with her standard outfit and can unlock the Supreme One outfit (from A Sitch in Time), her black leather jacket plus helmet and green leather jacket (Beuno Nacho), a recolored version of Kim's battle suit, her fur jacket (Emotion Sickness), and when all Kimmunicator tokens are collected, Kim's mission outfit.
Rufus, being a naked mole rat, does not benefit from this.
- Grappling hook: Used for swinging over gaps, unchanged from previous games.
- Gum: Used to activate switches and to hold all but heavy and stealth henchmen in place, leaving them vulnerable to being defeated in one hit.
- Electro Magnetic Scrambler: Used to reveal hidden objects, such as platforms and stealth-using enemies. Unlike the one in So The Drama, it does nothing but disable stealth and does nothing to robotic enemies.
- Grapple beam: This is Shego's version of Kim's grappling hook and although it has a different animation, it is functionally the same.
- Magne-Go: Used to bring objects and enemies towards you, and is useful in pulling ranged henchmen towards Shego or pulling henchmen into gaps to get rid of them without having to fight them (but you will be unable to collect any tokens from them!)
- EMPunch: Used to deactivate green electrical boxes and also has combat applications as it stuns enemies when used.
- The game was featured in a demo on Official Playstation Magazine's demo disc issue 111. Although not appeared to be reviewed, the inclusion of the demo appears to show that the editors had high hopes for the game, as demo discs in the magazines have demos for games editors want for readers to keep an eye on.
- All of the show's main stars voice their respective characters, such as Christy Carlson Romano as Kim Possible, Will Friedle as Ron Stoppable, Nancy Cartwright as Rufus, Tahj Mowry as Wade, John Di Maggio as Dr. Drakken, and Nicole Sullivan as Shego.