Despite the name, Mecha Bowser bears very little resemblance to Bowser, unlike the similarly named robot from Super Mario Sunshine. Its only similarities in appearance to Bowser are its spiked green shell, the spiky collar, and a red protrusion coming out of its head that vaguely resembles Bowser's hair. Mecha Bowser is a tall, old fashioned-looking blue and green toy robot with wheels on its feet and wind-up keys coming out of the sides of its head and its back.
CombatMario first arrives at Mecha Bowser's planet, he will land on a large conveyor belt. From here, he must Wall Jump his way on top of the robot's feet. There is a blue screw on each leg; screwing them both in makes a Launch Star appear, which will launch Mario onto the green section of Mecha Bowser's torso. There are four yellow screws here, and Mario must unscrew them while avoiding Firebars. Doing so will cause that layer of green to fall off, revealing a Mechakoopa and a Warp Pipe. The pipe will take Mario to an area near Mecha Bowser's arm with two Mechakoopas. Mario must climb on the arm and unscrew another yellow screw while avoiding two Swoops. Unscrewing the screw causes the arm to break off and a Launch Star to appear; Mario must use the Launch Star quickly or he will go down with the arm. The Launch Star takes Mario to a green path in front of Mecha Bowser's face. There is a Spring Mushroom nearby; Mario should grab it and hop down the path while avoiding the fireballs being launched by a Magikoopa as well as the ones coming out of Mecha Bowser's "mouth". On top of the robot's "nose" is a Sentry Beam that will attempt to hit Mario with its laser. Finally, once on top of the robot's head, there is a stack of Stone Wheels that, when Ground Pounded, causes the robot to explode, leaving the conveyor belt, a star, and the freed Gearmos that were locked inside it.