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