Here is the full list of all 40 Shellshock 2: Blood Trails achievements worth 1,000 gamerscore.
Completed Mission 6 on Normal
Completed Mission 6 on Hard
Completed Mission 7 on Hard
Completed the game on Normal
Completed the game on Hard
Completed Mission 7 on Normal
Completed Mission 8 on Normal
Completed Mission 9 on Normal
Completed Mission 10 on Normal
Completed Mission 8 on Hard
Completed Mission 9 on Hard
Completed Mission 10 on Hard
Completed the game twice
Completed Mission 5 on Normal
Completed Mission 5 on Hard
Completed Mission 4 on Normal
Completed Mission 4 on Hard
Completed Mission 3 on Normal
Completed Mission 3 on Hard
Completed Mission 2 on Normal
Completed Mission 2 on Hard
Completed Mission 1 on Normal
Completed Mission 1 on Hard
Completed a level firing only a pistol
Killed 15 enemies with the machete
Beaten down 15 enemies
Completed the game on Easy
Completed the game without being killed by an Infected
Found and picked up every weapon
Killed 15 enemies with one belt of a non-mounted Heavy Machine Gun
Dismembered 50 enemies
Scored 15 decapitating head shots
Completed a level without dying
Killed 150 enemies
Killed 5 enemies with one M16 clip
Killed 3 enemies with one rocket or grenade
Killed 5 enemies with one AK47 clip
Scored a decapitating head shot
Killed 3 enemies with one pistol clip
Beaten down an enemy