Complete the following achievements to unlock Microsoft Gamerscore points.

Achievement	How to unlock
Combat Experience ( 10 points )	Kill 50 enemies in the campaign on any difficulty.
Defender ( 20 points )	Help defend the barricade in New York on Normal or higher difficulty.
Dolly Madison Award ( 20 points )	Save the Constitution from being burned on Normal or higher difficulty.
Environmentalism ( 15 points )	Complete 40 environmental or grapple kills on any difficulty.
Exploding Monkey ( 20 points )	Kill at least four enemies with one explosion on any difficulty.
First Time for Everything ( 5 points )	Finish a multiplayer game.
Gravity is a Harsh Mistress ( 5 points )	Toss a paratrooper onto the streets below New York on any difficulty.
MVP ( 15 points )	Win an 8-player ranked or player match in Team Deathmatch mode with the highest score.
Next Time Take the Stairs ( 5 points )	Fall to your death during a multiplayer game.
One in the Chamber ( 10 points )	Kill a player in a ranked match with the last bullet in a pistol clip.
pwnt ( 15 points )	Finish an 8-player ranked or player match in Deathmatch mode with the highest number of kills.
Reservation for One ( 5 points )	Make your way down to Hotal Langteau on Normal or higher difficulty.
Sharpshooter ( 10 points )	Kill all the paratroopers as you make your way down the skyscraper on any difficulty.
Swirly Time! ( 5 points )	Drown a German in a toilet in the Tower of London on any difficulty.
TV Repairs ( 5 points )	Smash an enemy's head through a TV in the White House on any difficulty.
World Tour ( 15 points )	Finish a multiplayer game on every map in every mode.