Sonic the Hedgehog 2

From Sega Wiki

Sonic the Hedgehog 2 was released to the Sega Master System, Sega Game Gear, and Sega Genesis. On the Genesis, it marked the debut of the spindash. For both systems, it marked the debut of Tails.

Tail's cousin Guss was originally set to appear in the Genesis version, but due to memory, he couldn't, (he can be playable with a Game Genie). If you need more info on Guss, please look up the Tails and Guss article on this wiki.

Sonic games
Console games (main series): Sonic (SMD) · Sonic 2 · Sonic CD · Sonic 3 · Sonic and Knuckles · Adventure · Adventure 2 · Heroes · Shadow · Sonic (360/PS3) · Unleashed
Handheld games: Sonic (GG/MS) · Sonic 2 (GG/MS) · Chaos · Triple Trouble · Labyrinth · Blast · Pocket Adventure · Advance · Advance 2 · Battle · Advance 3 · Rush · Advance 2 · Genesis · Rivals · Rush Adventure · Rivals 2 · Chronicles
Spinoffs: SegaSonic · Spinball · Drift · Dr. Robotnik's Mean Bean Machine · Tails' Skypatrol · Tails Adventure · Knuckles' Chaotix · Fighters · 3D Blast · R · Shuffle · Pinball Party · Riders · Secret Rings · Mario & Sonic · Riders: Zero Gravity · Black Knight
Compilations: Compilation · Jam · Sonic & Knuckles Collection · Mega Collection (Plus) · Gems Collection