Here is the full list of all 12 Lara Croft and the Guardian of Light achievements worth 200 gamerscore.
Earn the top score objective in any level
Jump from Totec's shield while he is jumping
Collect all 10 red skulls in any single level
Catch Totec with the grapple while he is jumping over a death fall
Play Co-op mode
Activate all of the spikes at once in the Spider Tomb spike field
Kill 3 enemies with one bomb
Complete any level-specific Reward Challenge
Reflect an enemy's projectile back to him using Totec's shield
Collect all relics, artifacts and weapons