Teenage Mutant Ninja Turtles III: The Manhattan Project is a side-scrolling beat-'em-up. The game features play mechanics similar to the previous game, Teenage Mutant Ninja Turtles II: The Arcade Game, but it is an original title for the NES without any preceding arcade version.
The game begins with the Turtles spending their vacation in Key West, Florida. While watching April O'Neil's latest news report, her broadcast is suddenly hijacked by the Turtles' nemesis, Shredder. Taking April as his hostage, Shredder reveals that he has also turned the entire borough of Manhattan into a floating island and challenges the Turtles to come to his lair to stop him.
