"Spartan in Training- 50 GS: On Legendary, fight 4 Brute Cheiftains...and Win" "Get Some!- 25 GS: On Legendary, kill a Brute Cheiftain and his pack with only a shotgun" "Mean, Green, Killing Machine- 15 GS: Destroy an enemy vehicle with the Fuel Rod Gun" "Happy Go Lucky Grunts- 5 GS: Kill a pack of grunts with 1 stick grenade" "Keep It Clean- 15 GS: On Normal difficulty or above, assassinate a Brute Cheiftain" "Stay Calm- 15 GS: On Normal difficulty or above, Spartan Lazer a Ghost charging at you" "Sweep the Streets- 15 GS: On Normal difficulty or above, kill an enemy group with just a SOCOM Pistol" "Scream, Aim, and Fire- 25 GS: On Legendary 4 Player Live Co-Op, Kill 2 Hunters with only grenades" "Hunter Hunters- 25 GS: On Legendary, Kill all the Hunters in the game" "The Brutes Been Shot- 25 GS: On Normal difficulty or above, kill a Brute with a brute shot" "Stop, Drop and Roll- 5 GS: On any difficulty, get your first kill of the game with a grenade" "Go Green- 5 GS: kill an enemy using the environment" (e.g. explosive barrels) "No Spartan Shield Here- 15 GS: On Firefight, destroy a wall and the enemy behind it" "Flashback Johnson- 20 GS: On Firefight, Use the Spartan Lazer before dying" That's all i got, hope some of them are used [Edited on 06.20.2009 9:59 PM PDT]