Full list of all 78 Gears of War 2 (JP) achievements worth 1,750 gamerscore. It takes around 300-500 hours to unlock all of the achievements on Xbox 360.
Earn enough multiplayer experience to reach level 100 (Horde or Public only)
Kill 100,000 enemies (any mode)
Reached level 95 in multiplayer exeprience
Reached level 90 in multiplayer exeprience
Reached level 85 in multiplayer exeprience
Team survived all 50 Horde waves on all shipped maps
Played 1999 rounds in multiplayer
Team survived first 10 Horde waves on all shipped maps
Reached level 80 in multiplayer exeprience
Reached level 75 in multiplayer exeprience
Reached level 70 in multiplayer exeprience
Reached level 65 in multiplayer exeprience
Reached level 60 in multiplayer exeprience
Reached level 55 in multiplayer exeprience
Reached level 50 in multiplayer exeprience
Reached level 45 in multiplayer exeprience
Reached level 40 in multiplayer exeprience
Cooked up some Bloodmount BBQ with 25 roastings
Won 3 matches of Wingman (public party)
Reached level 35 in multiplayer exeprience
Team survived all 50 Horde waves
Reached level 30 in multiplayer exeprience
Won 10 rounds of Guardian as the leader (public party)
Reached level 25 in multiplayer exeprience
Reached level 20 in multiplayer exeprience
Team survived 10 Horde waves
Reached level 15 in multiplayer exeprience
Reached level 12 in multiplayer exeprience
Reached level 10 in multiplayer exeprience
Reached level 8 in multiplayer exeprience
Won 3 matches of King of the Hill (public party)
Captured 10 meatflags (public party)
Reached level 5 in multiplayer exeprience
Won a match on every map shipped with the game
Played a multiplayer match on all 29 shipped maps
Made it through "Road to Ruin" dressed as a Theron Guard
Won all Training Grounds matches
Made it through "Road to Ruin" with nothing but vengeance on your mind
Made it through "Road to Ruin" with a friend
Executioner with style
Killed 10 enemies with a grenade while down but not out
Used 10 meatshields to survive
Won 10 chainsaw duels
Completed all campaign acts on Normal Difficulty
Completed all campaign acts on Hardcore Difficulty
Completed all campaign acts on Insane Difficulty
Effectively used grenade mines
Killed 30 enemies with your Mulcher turret
Recovered all 41 collectibles
Defeated the Lambent Brumak
Completed all campaign acts on Casual Difficulty
Completed all acts in Co-op on any difficulty
Captured a Brumak
Killed an enemy with every weapon
Successfully defended COG headquarters
Defeated Skorge and his Hydra
Found the Locust queen
Killed 30 enemies raining down death from the sky
Activated Jack as homing beacon in Nexus
Found Maria
Got up close and personal with the Boomshield
Defeated the Leviathan
Arrived safely at Mount Kadar Stranded camp
Recovered 20 of 41 collectibles
Discovered the location of the Locust queen
Torched 30 enemies
Performed a chainsaw multiple bypass
Freed Baird from capture
Completed 10 chapters in Co-op on any difficulty
Watched Ilima sink
Bashed 30 Tickers
Mastered the ways of the Active Reload
Seen the sights with Betty
Escorted Betty to Landown
Successfully defended the hospital
Recovered 5 of 41 collectibles
Completed 1 chapter in Co-op on any difficulty
Showed Carmine the ropes