Ocean Wind Zone

Ocean Wind Zone is the name of an unused zone from Sonic the Hedgehog 2, set to be the second zone after Emerald Hill Zone. Much like many other zones intended to appear in Sonic 2, the zone was scrapped during development.

Contents
Judging by the concept artwork, Ocean Wind Zone was going to be a coastal level where Sonic would run across wooden piers build along the ocean. There would be cliffside terrain in the background, as well as islands similar to the ones seen in the background of Emerald Hill Zone. At some point in the level, Sonic would've been able to either run off of a pier ramp or run across a cliff wall.

Remnants
Based on Ocean Wind Zone's intended placement in the game, Level $01 is likely the remnants of this level. Even in the prototypes for Sonic the Hedgehog 2, there is no content to be seen within Ocean Wind Zone. In the final game, it takes the form of an Emerald Hill Zone duplicate with no collision.