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.
Team survived all 50 Horde waves on all shipped maps
Team survived first 10 Horde waves on all shipped maps
Earn enough multiplayer experience to reach level 100 (Horde or Public only)
Reached level 95 in multiplayer exeprience
Reached level 90 in multiplayer exeprience
Kill 100,000 enemies (any mode)
Reached level 85 in multiplayer exeprience
Reached level 80 in multiplayer exeprience
Played 1999 rounds in multiplayer
Reached level 75 in multiplayer exeprience
Reached level 70 in multiplayer exeprience
Team survived all 50 Horde waves
Reached level 65 in multiplayer exeprience
Captured 10 meatflags (public party)
Won 10 rounds of Guardian as the leader (public party)
Won 3 matches of Wingman (public party)
Won 3 matches of King of the Hill (public party)
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
Reached level 35 in multiplayer exeprience
Reached level 30 in multiplayer exeprience
Reached level 25 in multiplayer exeprience
Reached level 20 in multiplayer exeprience
Reached level 15 in multiplayer exeprience
Reached level 12 in multiplayer exeprience
Reached level 10 in multiplayer exeprience
Reached level 8 in multiplayer exeprience
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
Completed all acts in Co-op on any difficulty
Completed all campaign acts on Normal Difficulty
Completed all campaign acts on Hardcore Difficulty
Completed all campaign acts on Insane Difficulty
Cooked up some Bloodmount BBQ with 25 roastings
Team survived 10 Horde waves
Completed 10 chapters in Co-op on any difficulty
Completed 1 chapter in Co-op on any difficulty
Killed 10 enemies with a grenade while down but not out
Made it through "Road to Ruin" with nothing but vengeance on your mind
Made it through "Road to Ruin" with a friend
Made it through "Road to Ruin" dressed as a Theron Guard
Executioner with style
Won 10 chainsaw duels
Killed an enemy with every weapon
Won all Training Grounds matches
Defeated the Lambent Brumak
Completed all campaign acts on Casual Difficulty
Recovered all 41 collectibles
Captured a Brumak
Successfully defended COG headquarters
Defeated Skorge and his Hydra
Found the Locust queen
Killed 30 enemies with your Mulcher turret
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
Discovered the location of the Locust queen
Torched 30 enemies
Performed a chainsaw multiple bypass
Recovered 20 of 41 collectibles
Used 10 meatshields to survive
Freed Baird from capture
Watched Ilima sink
Mastered the ways of the Active Reload
Bashed 30 Tickers
Killed 30 enemies raining down death from the sky
Seen the sights with Betty
Effectively used grenade mines
Escorted Betty to Landown
Successfully defended the hospital
Recovered 5 of 41 collectibles
Showed Carmine the ropes