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