Here is the full list of all 40 Sniper: Ghost Warrior Contracts achievements worth 1,000 gamerscore.
Eliminate Main Target when in the vechicle with the Mine
Complete 24 Challenges
Buy 57 skills
Complete 9 of the Bounties
Complete SIBIRSKAYA-7 JUNCTION Region on the highest difficulty
Kill enemy from each sniper rifle
Kill 3 Enemies with 1 bullet
Unlock 10 Sniper Rifles
Complete SIBIRSKAYA-7 JUNCTION Region
Complete 24 Contracts
Complete ARAKCHEYEV FORTRESS Region
Unlock 5 Regions
Complete ARAKCHEYEV FORTRESS Region on the highest difficulty
Exfiltrate in under 1 minute after killing Igor Sekhov
Kill enemy from zip line
Complete 13 of Challenges
Eliminate Main Target with The Chain kill
Complete 5 of the Bounties
Kill an Enemy from a 500 meters distance.
Eliminate Main Target with Death from above
Buy 28 skills
Unlock 14 Gadgets
Eliminate Main Target with Remote Sniper Turret
Unlock 7 Sidearms
Complete BEKETOV VALLEY Region on the highest difficulty
Complete BEKETOV VALLEY Region
Complete 13 Contracts
Find 14 collectibles
Complete ALTAI MOUNTAINS Region on the highest difficulty
Complete KOLCHAK HARBOR 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
Find the first collectible
Complete first Bounty
Interrogate an Officer
Complete first Challenge
Complete first Contract