Full list of all 12 Sonic The Hedgehog 2 achievements worth 200 gamerscore. It takes around 3-4 hours to unlock all of the achievements on Xbox 360.
You won 10 versus zones on Xbox Live.
You beat the game in under an hour.
You beat Chemical Plant Zone 1 in under 45 seconds.
You beat the game.
You beat Emerald Hill Zone 1 in under 35 seconds in single-player or co-op mode.
You played all four multiplayer zones.
You got to the Casino Night Zone.
You stayed in Super Sonic mode for one minute.
You became Super Sonic.
You got all the Chaos Emeralds.
You cleared the Emerald Hill Zone 1.
You got one Chaos Emerald.