Full list of all 50 Hour of Victory achievements worth 1,000 gamerscore. It takes around 20-25 hours to unlock all of the achievements on Xbox 360.
Save 50 flags in Capture the Flag ranked matches
Disarm 50 bombs in Devastation ranked matches
Destroy 25 Targets in Devastation ranked matches
Score the tie breaker in a Devastation ranked match in the last 10 seconds
Host active multiplayer games for 20 hours
Complete a game in all Multiplayer Modes
Capture 25 flags in Capture the Flag ranked matches
Place first in a ranked match, all three game types
Kill 100 enemies in ranked matches
Kill 10 enemies in a row in a ranked match without dying
Run out of all your ammo in a ranked match
Stealth kill 25 enemies
Complete Critical Mass with Ross
Complete Strategy by the Book with Ross
Place first in a multiplayer game on the losing team
Complete The Hallowed Halls with Ross
Complete The Net Tightens with Ross
Complete Ascension with Ross
Complete Hell from Above with Ross
Complete The Hill with Ross
Complete Barbarians at the Gate with Ross
Complete Critical Mass with Taggert
Complete Strategy by the Book with Taggert
Complete The Hallowed Halls with Taggert
Complete The Net Tightens with Taggert
Complete Ascension with Taggert
Complete Hell from Above with Taggert
Complete The Hill with Taggert
Complete Barbarians at the Gate with Taggert
Complete every campaign
Complete a Multiplayer Game
Complete Desperate Measures campaign on any difficulty level
Complete Critical Mass with Bull
Complete Strategy by the Book with Bull
Complete The Hallowed Halls with Bull
Complete Clash of the Titans
Complete The Raid on Castle Festunburg campaign on any difficulty level
Take out 500 enemies in any mode
Complete The Net Tightens with Bull
Grenade 50 enemies in any mode
Complete Breakout
Complete Ascension with Bull
Snipe 75 enemies in any mode
Complete The Liberation of Al Shatar campaign on any difficulty level
Complete Hell from Above with Bull
Take out 100 enemies in any mode
Complete The Hill with Bull
Take out 20 enemies with a headshot in any mode
Complete Barbarians at the Gate with Bull
Take out 10 enemies in any mode