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