Nicktoons Unite! is a 2005 video game featuring characters and levels from Nickelodeon's flagships at the time; SpongeBob SquarePants, Danny Phantom, The Fairly Oddparents and Jimmy Neutron. It has spawned a total of 3 sequels, Nicktoons: Battle for Volcano Island (2006), Nicktoons: Attack of the Toybots (2007) and Nicktoons: Globs of Doom (2008). Even though this is the first official Nicktoons Crossover, this is not the first video game that included characters from more than one show. The game was released for the GameCube, Playstation 2, Gameboy Advance and Nintendo DS.
On one ordinary morning, SpongeBob comes out of his house asking Gary what to do and then saying he will visit Patrick with him after meowing, but then hears that Plankton has taken over Bikini Bottom after him announcing that him and the Syndicate will rule Bikini Bottom. Then Plankton uses multiple tank-like vehicles to vacuum all of the town's citizens. SpongeBob tiptoes to the side of his pineapple and suddenly Goddard teleports from a portal to the side of SpongeBob's pineapple and petrifies him. Then, SpongeBob receives a message from Jimmy Neutron through Goddard telling him about Plankton teaming up with villains from other worlds. SpongeBob follows Goddard through the green portal to meet Jimmy Neutron, Timmy Turner and Danny Phantom. Since SpongeBob is a sea sponge and is always in need of water, Jimmy uses his Neutronic Moisture Sealer to coat SpongeBob in a coat of self regenerating moisture. Jimmy then explains this all started when Prof. Calamitous somehow managed to gain access to his project plans for his latest invention, The Universe Portal Machine, a device that lets us travel to other worlds. With the project plans, Calamitous created his own Universe Portal Machine. He took a journey to each world and met up with an ally from every world, Plankton, Vlad Plasmius and Denzel Crocker and then teamed up to form a Syndicate. Jimmy suspects that the four of the villains have a master plan in which they can all benefit from. They have combined their powers to form an army of Syndicate troops and are now stealing energy from each of the four worlds, our heroes don't know why they're stealing the energy, but whatever it's for, it can't be good! Since our heroes don't know where Calamitous' lair is, they began by rescuing their world’s first.
SpongeBob SquarePants, Danny Phantom, Timmy Turner and Jimmy Neutron are the only four playable characters in the game.
In the console version a player can play with 3 CPUS or with a friend or two with the remaining computer(s). All characters have different types of abilities, which they can switch from. There are also things you will need a certain character's ability to do. For example, SpongeBob can use Bubble Bombs to blow up pillars, Danny can perform Ghostly Wail on some types of glass, Timmy is able to use his Freeze Glove to freeze some waters and glowing blue objects and Jimmy is needed to use his Shrink Ray to shrink down certain items that you can use to jump on and reach new heights.
References to Jimmy Neutron series
Jimmy Neutron and Professor Calamitous are the respective main protagonist and antagonist of the game, as they are both responsible for tampering with multiverse travel. Calamitous is also the founder of the Evil Syndicate, which consists of other Nicktoons villains. As a means to fight back, Jimmy summons the heroes of the various dimensions to form an alliance.
Ironically, unlike the three other franchises represented, there isn't a section dedicated to Jimmy's own home world. Instead, Goddard's inner workings take place for such a level, with a holographic recreation of Jimmy's backyard being the closest to an actual Neutron-themed world. However, Jimmy's Lab is the main hub, with specific sections being unlocked after the completion of each level.
- Jimmy refers to Cosmo and Wanda as Timmy's "holograms," even though by the end of Jimmy Timmy Power Hour, he called them "reality-bending computer programs."
- In the Game Boy Advance version, in Timmy's Home level, when Timmy says, "Hey, why are there robots in my house?" the player can see Jimmy's room in the background.
- In the console version, unless Jimmy somehow got Danny after and quicker than he got SpongeBob, it is unknown how Danny did not know that SpongeBob talked as he should have heard and possibly seen SpongeBob taking in his part of the conversation which occurred moments earlier.
- In the console version, in the second cutscene, each of the members of the Syndicate is shown on Jimmy's computer. Professor Calamitous is shown in 2D, as opposed to CGI, which is the animation that the show is in.