There is also an upgrade system in the game. Although the player only needs to complete a level's main component in order to unlock the next level, it is not possible to complete the game only doing the main levels (though the player does not need to do all of the side tasks). Each main level and side task will give the player a Goofy Goober Token once completed, and the player needs these tokens to learn certain skills and proceed to the game. Boss enemies include the giant frogfish from the film, Dennis (who is fought twice), and King Neptune. Four levels involve a boss enemy that the player must defeat to progress to the next level. Each level contains a main objective and side tasks. The player controls SpongeBob SquarePants and Patrick Star, both of whom have their own unique set of abilities. There are 18 levels in the game that loosely follow the storyline of the film. The gameplay is similar to that from Heavy Iron Studios' previous game, Battle for Bikini Bottom, as it was created using the same engine and shares many assets. King Neptune's crown has been stolen by Plankton and SpongeBob and Patrick must retrieve it from Shell City and save Bikini Bottom. They are likely destroyed afterward.The plot of the video game is based on the film, albeit liberties are taken occasionally. However, at that moment, the Duplicatotron 3000 malfunctioned and rapidly created more giant robotic versions of Plankton, where they all begin arguing with each other about destroying each other. When SpongeBot SteelPants is defeated the first time, Robot Plankton rants about it and fixes the SpongeBot by giving it anchor arms to strengthen it. He then flies into SpongeBot's ear and SpongeBob has to fight him in SpongeBot's brain. After he defeats them both, Robot Plankton swears revenge on SpongeBob. SpongeBob then goes to battle SpongeBot SteelPants and Robot Plankton. Plankton tries to fix the problem only to realize that all the robots are instead obeying a giant robotic version of himself. Plankton says they were supposed to help him steal the Krabby Patty Formula, but instead they ran amok around Bikini Bottom under nobody's command as Plankton forgot to have the switch on his robot making machine set to "OBEY PLANKTON" as it was set to "DON'T OBEY PLANKTON". After fighting their way through many robots, SpongeBob and his friends enter the Chum Bucket and find a giant version of SpongeBob, and discover Plankton was the one who made the robots.