Genocide City Zone
From Sonic Retro
Genocide City Zone is an empty level in the Sonic 2 Beta ROM. CPZ music plays, and Sonic and Tails fall to their death at the bottom of the stage. The only objects that this level has in debug mode are the two default objects, a ring and a teleport monitor.
Tom Payne, the zone artist in charge of this level, stated that it was dropped before it was even started. Instead, he worked in the third act of Metropolis.