Here is the full list of all 50 X-Men Origins: Wolverine achievements worth 1,000 gamerscore.
Defeated David Nord (Agent Zero)
Killed 500 enemies
Lunged to 250 enemies
Found 1/2 of all Dog Tags in the game
Killed 25 Ghosts with their own weapon
Got 6 enemies airborne at once
Dismembered 100 enemies
Killed 200 enemies with Claw Spin
Killed 200 enemies in Feral Sense
Killed 10 enemies using objects in the environment
Killed 30 enemies using objects in the environment
Killed 50 enemies while in Berserker mode
You found the cake, yummy!
Beat the game on Hard Difficulty
Raised All Combat Reflexes to Master Level
Found all Dog Tags in the game
Maxed out all upgrades
Killed 2000 enemies
Light 20 enemies on fire
Killed 25 enemies with a reflected projectile
Fought 4 W.E.N.D.I.G.0 prototypes at the same time and defeated them at Alkali lake.
Raised One Combat Reflex to Master Level
You feel cold as you examine the skeleton and read the name "Arthas" etched into the nearby sword
Defeated Weapon 11 (Deadpool)
Completed the Jungle Mission
Performed 10 Air Grabs
Defeated Remy LeBeau (Gambit)
Killed 150 enemies while in Berserker mode
Defeated Fred Dukes (The Blob)
Destroyed all objects in the grocery store fight with Fred Dukes (The Blob)
Defeated the Sentinel Mark I
Flew through the O ring in the Sentinel Boss Battle
Raised one Mutagen to level 3
Performed a Wolverine to Wolverine Lunge
Killed 10 enemies by throwing them off high areas
Performed 25 Counter moves
Escapes from Weapon X
Killed 6 enemies with a single attack
Killed 1 enemy with a reflected projectile
Quick Killed 20 enemies
Lunged to 100 enemies
Lunged to a W.E.N.D.I.G.0 prototype's back
Quick Killed 3 enemies in a row
Defeated Victor Creed (Sabretooth)
Performed 1 Counter move
Impaled Victor Creed outside the Bar
Killed 100 enemies
You found a mysterious hatch!
Lunged to 25 enemies
Quick Killed 1 enemy