SpongeBob SquarePants: Battle for Bikini Bottom is a video game based on the television show SpongeBob SquarePants. The game has been released for the Game Boy Advance, Nintendo GameCube, PC, PlayStation 2, and Xbox consoles (the Xbox version is backwards compatible for the Xbox 360 console). The player attempts to defend Bikini Bottom from an invasion of robots created by Plankton with a machine called the Duplicatotron 3000. The playable characters are SpongeBob, Patrick, and Sandy. The Windows version features a series of mini-games and differs from the console versions.
Three types of items can be collected. Shiny objects are the game's currency, and can be used to pay tolls within game areas or to buy golden spatulas from Mr. Krabs. Golden spatulas are used to grant access to new areas, they are hidden throughout the game and can also be earned by completing tasks set by Squidward and several other characters from the cartoon. These tasks can involve defeating particular robots or searching for items. The other collectible item type, Patrick's socks, can be traded for golden spatulas.
Though some areas can be navigated by any character, several sections can only be completed with a specific character, due to each one having unique abilities. SpongeBob can create a bubble helmet for head-butting enemies, launch a bubble-blowing spin attack and double jump to reach higher platforms. Patrick can throw objects at switches, freeze goo rivers and attack enemies with a belly flop. Sandy can glide over large gaps and wields a lasso, with which she can tie up enemies or swing on hooks to reach distant areas.
Meanwhile, Spongebob is playing with his best friend, Patrick Star in his house. Patrick says that he has a shell that can recreate an item into many items. They were playing with toy robots at the time, and Patrick puts one toy robot in the shell and says the magic words he believes will make the robot duplicate itself. He says a long line of confusing and long, unknown words and shakes the shell. Then, they go to their respective houses and fall asleep.
The next day, Spongebob finds that robots have ransacked his house and invaded Bikini Bottom, his hometown. He believes it was Patrick's magic shell that made the robots real. Plankton is outside his house, and Spongebob questions why he's not at his house (also the Chum Bucket). Plankton says that robots invaded his house, forced him out, and started bending back his spoons. He tells Spongebob to force them out of the area before the robots bend back all his forks too. Spongebob accepts and the game begins.
Patrick states that the robots have stolen his socks, and if Spongebob finds ten of them, he'd give him a Golden Spatula. Mr. Krabs states in a telegram that if Spongebob were to find enough Shiny Objects (currency in the game), he'd also give Spongebob a Golden Spatula. The number of Shiny Objects increases each time he sells them to Mr. Krabs, the first Golden Spatula for 3,000 Shiny Objects, and increasing by 500 each Spatula.
Spongebob must find Golden Spatulas to enter different areas. The first available being Spongebob's House, then Bikini Bottom, Jellyfish Fields, Downtown Bikini Bottom, Goo Lagoon, central Bikini Bottom (still in the level screen called Bikini Bottom but 15 golden spatulas are needed to enter), Rock Bottom, Sand Mountain, the Mermalair, south Bikini Bottom (also in Bikini Bottom but 40 golden spatulas are needed to enter), the Kelp Forest, the Flying Dutchman's Graveyard, Spongebob's Dream, and finally the Chum Bucket. A new boss is faced every time entering a brand-new part of Bikini Bottom.
After beating Robo-Sandy (In Posiedome, before entering central Bikini Bottom) and Robo-Patrick (In the Industrial Park, before entering south Bikini Bottom), SpongeBob discovers that Plankton was responsible for the robots (the proofs are that The Chum Bucket has a neon sign that says Robot Headquarters, a recipt for robot parts signed by Plankton, and a sign on a butt of a robot said Propety Of Plankton). You clear the Krusty Krab, solve all the problems in each dream bubble in SpongeBob's dream, save campers/students in the Kelp Forest, and convince the Flying Dutchman to give up his Golden Spatula. Gaining 75 spatulas, you enter Plankton's lab and discover a Robo-Plankton and Robo-SpongeBob (the player fights Robo-Spongebob and fights Robo-Plankton when you knock Robo-SpongeBob unconscious), who you defeat. After defeating him, SpongeBob follows Robo-Plankton into Robo-SpongeBob's head, where you reach the brain to bubble missile the main brain power generator. You then play as SpongeBall for the entire credit in a stadium for ball tricks
There is also a movie theater that can be accessed by paying a fee of 40,000 shiny objects. Once inside, the player is able to view some of the game's concept art.