Here is the full list of all 24 Sniper: Ghost Warrior achievements.
Finish the game on Hard difficulty.
Kill 250 people using pistol. (Multiplayer)
Kill 10 enemies with throwing knives.
Shoot 5 cable lines using sniper rifles.
Kill 250 people using sniper rifle. (Multiplayer)
Kill 500 people using sniper rifle. (Multiplayer)
Kill 2000 enemies. (Multiplayer)
Win 50 rounds playing online. (Multiplayer)
Deliver 100 headshots.
Kill 10 birds.
Collect all secrets.
Kill 2 enemy with one grenade.
Complete Act 4.
Finish the game on Easy difficulty.
Finish the game on Normal difficulty.
Complete Act 3.
Kill a total of 30 enemies with Browning gun.
Complete Act 2.
Deliver 50 headshots.
Kill all enemies attacking your pontoon from the riverside on 'Weaken The Regime' level.
Complete Act 1.
Shoot an enemy through a wall.
Kill 15 enemy using concentration mode.
Kill 2 enemy with one shot.