After falling through the tunnel, Vince finds himself in the underground city of Roachfort, where he meets Professor Ethel, an egotistical turtle who is trying to make a balloon that will take them back to the surface. The professor sends Vince through Roachfort to gather supplies for the balloon, but when it is complete the balloon fails to take off due to too much weight. The professor chooses between her personal belongings and Vince, and decides to throw Vince off. After defeating the “obligatory boss battle”, a two-headed cyclopian alligator named Two-Eyes, Vince finds a tank of helium, which he uses to inflate himself and rise to the surface.
In the Carnival DePrave, Vince has to face down some more challenges. Kosmo has set up for him to activate the carnival’s rides in order to reach a runway with a motorcycle that Vince can use to jump into the Big Top, where Madam Charmaine is being held. Upon entering the Big Top, Vince finds that Kosmo is piloting a massive robot, called the “Kosmobot”, which he then tries to use to crush Vince. Vince manages to hurt himself, dismantling the robot’s legs. He then has to climb up the robot to get to an airplane, which he uses to fly into the robot’s head. Inside the head, Vince climbs to the top and attacks the brain, destroying the robot. Vince manages to get out just in time before the robot explodes. But just as Vince is celebrating his triumph, he realizes he forgot Madam Charmaine and turns around. Fortunately, Madam Charmaine is fine, as are Kosmo and his henchmen. Kosmo attempts to use his last bit of Zombie Dust to defeat Madam Charmaine, but she easily repels the attack. Using some Zombie Dust Vince gives her, Madam Charmaine uses her magic to turn Kosmo and his henchmen into balloons. Then, Vince pops them using his powers and with their enemy gone at last, Vince and Madam Charmaine start the journey back home. As the credits roll, Vince questions Madam Charmaine on why, because she so powerful, she can’t provide a decent home and even a second eye.