Here is the full list of all 35 Far Cry Instincts Predator achievements worth 1,000 gamerscore.
Instincts Story finished at Predator difficulty level
Instincts Story completed at all difficulty levels
Instincts Story and Evolution Story completed at all difficulty levels
Instincts Story finished at Rookie difficulty level
All of Krieger's lost research found
Evolution Story finished at Rookie difficulty level
Finish the Expansion Story at all difficulty levels
Evolution Story finished at Predator difficulty level
Evolution Story finished at Hunter difficulty level
Instincts Story and Evolution Story completed
40 Stealth kills in any solo mode
80 hours played in Multiplayer Mode
300 Headshots in any Multiplayer Game Mode
1000 Total Kills reached in any Multiplayer Game Mode
200 Grenade kills in any Multiplayer Game Mode
150 Feral punch kills reached in any Multiplayer Game Mode
100 Road kills in any Multiplayer Game Mode
100 Traps kills in any Multiplayer Game Mode
10 Kills in Multikill in any Multiplayer Game Mode
300 games in whatever Mode won
50 games in Capture the Sample Mode won
Steal the Sample Mode winner once
All online Game Mode won once
50 games in Predator Mode won
Predator Mode winner once
50 games in Seek n' Secure Mode won
Seek n' Secure Mode winner once
50 games in Team Chaos Mode won
Team Chaos Mode winner once
50 games in Chaos Mode won
Chaos Mode winner once
Instincts Story finished at Hunter difficulty level
50 Trap kills in any solo mode
100 Headshots in any solo mode
80 Feral punch kills reached in any solo mode