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