Accomplish the indicated achievement to get the corresponding number of 
Gamerscore points:

Emerald Hill (5 points): Clear the Emerald Hill Zone 1. 
Fast Emerald (15 points): Beat Emerald Hill Zone 1 in under 35 seconds in 
single-player or co-op mode. 
Fast Chemical (20 points): Beat Chemical Plant Zone 1 in under 45 seconds. 
Casino (10 points): Get to the Casino Night Zone. 
Super Sonic (20 points): Become Super Sonic. 
Extended Super (20 points): Stay in Super Sonic mode for one minute. 
Chaos Emerald (10 points): Get one Chaos Emerald. 
Chaos Master (40 points): Get all the Chaos Emeralds. 
Conquering Time (10 points): Beat the game in under an hour. 
All Multiplayer (5 points): Play all four multiplayer zones. 
Xbox Live Racer (10 points): Win 10 versus zones on Xbox Live. 
Win (35 points): Complete the game.