Complete the following achievements to unlock Microsoft Gamerscore points.

Achievement	How to unlock
Drop A Quarter (10 points)	Complete a mission in Score Attack with at least 10,000 points.
Party Hearty (25 points)	Complete a mission in Score Attack co-op, with all participants scoring at least 200,000 points.
The Hare (20 points)	Beat the par time of a mission in Score Attack.
The Tortoise (50 points)	Complete a mission in Score Attack with at least 500,000 points.
Up For A Challenge (20 points)	Reach 50,000 points in Score Attack with a Skull multiplier of x2 or higher.