This takes place after the episode "Band Geeks," as evidenced by the fact that Mr. Krabs, SpongeBob, Sandy, Plankton, and Patrick had never seen a human before this episode, as referenced when Patrick said "These are some oddly looking fish." and SpongeBob saying "Maybe we're in one of those toxic waste dumps."
This takes place after the Jimmy Neutron and Fairly OddParents crossover, Jimmy Timmy Power Hour. As referenced by Jimmy and Timmy's knowledge of each other. As well as Jimmy's knowledge of Cosmo and Wanda. Also, Jimmy refers to Fairy World magic as "the power source from the game." Cindy also met Timmy in that episode, which is referenced at the end of Nicktoons Unite!.
It might also take place after Jimmy Timmy Power Hour 2: When Nerds Collide! because in that episode Mr. Crocker and Professor Calamitous had no interaction with each other after Professor Calamitous hit the "Welcome to Dimmsdale" sign when Mr. Crocker was putting up his birthday sign.
This takes place after Jimmy Neutron's Professor Calamitous, I Presume, and Danny Phantom's Bitter Reunions. As these we're the two episodes that Jimmy met Calamitous and Danny met Vlad.
This takes place after "Help Wanted" because SpongeBob knows Mr. Krabs.
This takes place after "Scaredy Pants" because SpongeBob knows the Flying Dutchman.
This also most likely takes place after "Shanghaied" because it seems like the Flying Dutchman knows him more and is also afraid of him and SpongeBob seems familiar with the Dutchman's ship.
This takes place after the Fairly OddParents' That Old Black Magic because Timmy has been to Fairy World.
This takes place after Fairly OddParents' Inspection Detection because Timmy knows Jorgen.
This takes place after the Oh Yeah Cartoons! short/Fairly OddParents' pilot, The Fairly OddParents! because Timmy knows Cosmo and Wanda.
This might takes place after Fairly OddParents' Abra-Catastrophe! because the exterior of Crocker's fortress looks similar to his fortress in that episode.
This takes place after Danny Phantom's One of a Kind because that is the episode where Danny met the Box Ghost and Skulker. (Skulker appeared in the episode below.)
This takes place after Danny Phantom's Prisoners of Love because that is the episode where Danny met Walker. He has also been to the Ghost Zone Prison before in that episode.
Because of that episode, this game is also after the episode Mystery Meat because that is the episode Danny met The Lunch Lady Ghost and she was in Prisoners of Love. Same with the episodes What you Want, Attack of the Killer Garage Sale, and Parental Bonding with the characters Desiree, Technus, and Princess Dorathea.
This takes place after "Frankendoodle" because that is the episode where SpongeBob met DoodleBob, which is used as an attack in Nicktoons Unite!.
Because of this, the game also takes place after "Bubblestand."
This game takes place after "Plankton!" because SpongeBob knows Karen.
This game takes place after The SpongeBob Movie: Sponge Out of Water because SpongeBob is not surprised when he sees humans and Plankton doesn't know what Teamwork is in that movie and in this game he works with a team.
This game takes place after the Danny Phantom episode, "Memory Blank" because Danny has his logo on his chest which he did not obtain until that episode.
Based off this game
This takes place after Nicktoons Unite! and Nicktoons: Battle for Volcano Island because SpongeBob, Danny, Timmy, Sam, Cosmo, Wanda, Jimmy, Patrick, and Professor Calamitous know each other. In addition, Calamitous is aware of fairy magic and Krabby Patties as he uses the Krabby Patties to make the fairies magically fart to allow his Toybots to be alive.
This takes place before SpongeBob SquarePants featuring Nicktoons: Globs of Doom. In SpongeBob SquarePants featuring Nicktoons: Globs of Doom, Danny, Tak, Plankton, SpongeBob, Patrick, and the Wise Old Crab knew each other (except for the Wise Old Crab with Plankton and Tak and Tak with Plankton)
This takes place before both Fairly Odd Baby and Fairly OddPet because both Poof and Sparky are not around with Timmy.
Since the first level takes place underwater, in the console version of the game Tak should not have been able to breathe in the cut scene because he never met Jimmy, who had in Nicktoons Unite! invented gum that allowed the other Nicktoons to breathe under water. Although, it is possible that his magic allows him to breathe.
This error isn't present in the DS or GBA versions of this game, as Tak had met Jimmy beforehand in the DS version and the first level didn't take place underwater in the GBA version.