Sonic the Hedgehog 2 has 11 zones. The 1992 Sega Genesis/Mega Drive platformer takes Sonic across themed areas, each built from one or more side-scrolling acts and usually ending with a battle against Dr. Robotnik.
The zone count includes familiar locations such as Emerald Hill, Chemical Plant, Aquatic Ruin, Casino Night, Mystic Cave, Metropolis, Sky Chase, and Wing Fortress. Most zones contain two acts, but the later areas use different structures. Metropolis Zone has three acts, while Sky Chase and Wing Fortress are shorter set pieces.
A common mix-up comes from counting levels rather than zones. The game is generally described as having 11 zones and 20 regular acts, although special stages, boss encounters, and regional or later-release differences can make informal counts vary. Hidden Palace Zone also complicates lists because it was cut from the original release and later restored in some versions.
Sonic 2 also introduced Tails and the Spin Dash, making its zone structure part of a broader expansion over the original game.