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