Will Wright floats on a "Sim's Diamond", also known as a plumb-bob.
Actually, the level ends after the incinerator is put off. After the cut scene, the modern part of the game engine becomes the new hub, and each character has to talk to Frink to get their powers, but this is different on each console.
In the PS2 version, only Homer and Lisa can be played while Bart and Marge walk around and Professor Frink stays in the little office in the middle of the place. They both have to talk to Professor Frink to get their new powers. They have to take the "Sim Diamond" that Frink launches so their corresponding items appear. Homer has to take the gumi that appears near him to become Gumi-Homer and attack the football players, while Lisa has to step on the Buddha's statue and use the Buddha's Hand thunder to defeat the football players. Bart and Marge get their powers automatically.
In the PS3 and Xbox version, the pixelated Simpsons are seen walking around and Frink's girlfriend, Koopa Troopa, is next to Frink in the office. When the Simpsons talk to Frink, he launches a power box instead of a diamond. Homer and Lisa get their powers in the same way like on the other version. Bart and Marge have to talk to Frink too, but do not practise their powers.
Once the Simpsons earn their new powers, four more levels open up in the portals.