So my brother is trying to find the identity on a pin. He said there was a "basement".

In the middle of the machine in the open area of the playfield, there is a glass insert that you can't see through until you drop the ball into a well that sends the ball under the main deck. The bottom playfield is then lit so you can see the ball under the glass, and there's another set of flippers oriented opposite of the normal flippers.

Ring a bell for anyone?