Here is the full list of all 43 Sniper Ghost Warrior Contracts 2 achievements.
Complete Mount Kuamar
Be within 2 meters of an enemy for 10 seconds without being detected
Kill 2 enemies with a grenade
Unlock 1 Weapon
Complete Zindah Province
Complete a contract when every time you hit the enemy is a kill
Kill at least 1 of each enemy type in the same mission
Land a shot from over 1300m away
Find your first Collectible
Kill 5 enemies in 1 minute without raising the alarm
Kill 2 enemies with the same bullet
Buy your first skill
Unlock all Sniper Rifles
Unlock all Secondary Weapons
Unlock all Sidearms
Buy 54 skills
Find all of the Collectibles
Complete Zindah Province at the Highest Difficulty in a single playthrough
Complete Mount Kuamar at the Highest Difficulty in a single playthrough
Complete The Tajmid Heights
Complete The Tajmid Heights at the Highest Difficulty in a single playthrough
Complete Rashida Qalat
Complete Rashida Qalat at the Highest Difficulty in a single playthrough
Complete Maladh Wadi
Complete Maladh Wadi at the Highest Difficulty in a single playthrough
Complete all Mission Contracts
Kill Antwana Zarza while he is in a vehicle
Kill Ronald Payne after he takes up a sniping position
Kill Novikov while he's inspecting a damaged Antenna
Escape the Server Room ambush without being detected
Kill everyone from all of the reinforcement waves during the Oil Field contract
Lead the prisoner to safety without raising the alarm
Provoke both targets to escape and kill them before they do so
Retrieve the security chips without killing Bibi
Kill Taj Taheer in the car with a headshot
Kill the Target and the other Suspects without raising the alarm
Kill each Suspect with a single bullet, hitting the body, during the alarm
Kill 2 enemies using an explosion
Kill 5 enemies in the same mission using the Sentry Turret
Kill any contract target using your drone's poison rifle
Finish a Contract using only sniper rifles
Finish all Contracts in a Region without ever taking damage from enemies
Kill 5 enemies while holding your breath with Stamina Booster active