Here is the full list of all 40 Sniper Ghost Warrior Contracts achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Eliminate Main Target when in the vechicle with the Mine
Eliminate Main Target with The Chain kill
Eliminate Main Target with Remote Sniper Turret
Kill 3 Enemies with 1 bullet
Eliminate Main Target with Death from above
Kill enemy from each sniper rifle
Complete SIBIRSKAYA-7 JUNCTION Region on the highest difficulty
Unlock 10 Sniper Rifles
Complete SIBIRSKAYA-7 JUNCTION Region
Complete 24 Contracts
Complete 9 of the Bounties
Unlock 7 Sidearms
Buy 57 skills
Kill an Enemy from a 500 meters distance.
Exfiltrate in under 1 minute after killing Igor Sekhov
Kill enemy from zip line
Complete ARAKCHEYEV FORTRESS Region on the highest difficulty
Unlock 5 Regions
Complete ARAKCHEYEV FORTRESS Region
Complete 24 Challenges
Unlock 14 Gadgets
Complete BEKETOV VALLEY Region on the highest difficulty
Complete BEKETOV VALLEY Region
Complete 13 Contracts
Complete 13 of Challenges
Find 14 collectibles
Complete 5 of the Bounties
Complete KOLCHAK HARBOR Region on the highest difficulty
Complete KOLCHAK HARBOR Region
Find 7 of collectibles
Complete ALTAI MOUNTAINS Region on the highest difficulty
Buy 28 skills
Interrogate an Officer
Find the first collectible
Complete ALTAI MOUNTAINS Region
Kill 80 enemies in single mission
Complete first Bounty
Buy your first skill
Complete first Challenge
Complete first Contract