Teenage Mutant Ninja Turtles is divided into six stages known as Areas. With a few exceptions, each Area consists of a large overworld where turtles can explore and look for entrances to buildings or subways or tunnels. While in the overhead view, turtles can walk in four directions and attack similar sized enemies, but they cannot withstand contact with larger vehicles unless they themselves are driving a vehicle.
Upon entering a doorway or manhole, the view will switch from overhead to a side-scrolling view. At this point, the active turtle has access to a wide range of attacks (high, middle, and low), as well as access to any special weapon they may have in their possession. Objectives in each interior range from merely reaching the opposite entrance, or collecting a particular item. Some interiors in Area 3 have sewer water flowing through them which, if a turtle falls into it, will sweep them back to the outside of the entrance they initially arrived from.
Each Area contains an ultimate objective, whether it's a boss that must be defeated or a challenge to overcome, before the story continues and the player advances to the next Area. There are no warps or the ability to choose which Area you travel to; each Area must be completed in sequence, beginning with Area 1. When you begin the game, you are informed that the Foot Clan has captured April O'Neil. Master Splinter instructs the four ninja turtles to rescue her.