Collect ALL 8 relics in the game and then at the 'Main' menu select 'Rewards' and choose the 'Special' option. Style Units is a pre-production test level which has aspects from every section of the game.

The following cheats and features are accessed by pausing the game and selecting the 'Options' menu. The Achievements can still be gained with these cheats activated.

Unlock ALL Regular Weapons (not Silver Mini SMGs or Golden Shotgun):
Complete ALL Greece Time Trials.

Unlock Silver Mini SMGs:
Complete ALL Lost Island Time Trials.

Unlock Golden Shotgun:
Complete ALL Lost Island Time Trials.

Unlock Textureless Mode:
Complete ALL Lost Island levels on any difficulty.

Unlock Infinite Breath:
Complete ALL Lost Island levels on any difficulty.

Unlock Infinite 50 Caliber Pistol Ammo:
Complete ALL Peru Time Trials.

Unlock Infinite Health:
Complete ALL Egypt Time Trials.

Unlock Infinite Mini SMG Ammo:
Complete ALL Egypt Time Trials.

Unlock Infinite Shotgun Ammo:
Complete ALL Greece Time Trials.

Show Enemy Health:
Complete ALL Peru Time Trials.

These are unlocked by completing the corresponding task, they are then started by pausing the game during a level when you see floating diamonds and going to the 'Options' menu and selecting the 'Display' option.

Unlock Peru Commentaries:
Complete ALL Peru levels.

Unlock Egypt Commentaries:
Complete ALL Egypt levels.

Unlock Greece Commentaries:
Complete ALL Greece levels.

Unlock Lost Island Commentaries:
Complete ALL Lost Island levels.

Complete the following tasks to get the GamerScore.

Weapon Master I - GamerScore 10:
Get the Magnum weapon.

Weapon Master II - GamerScore 10:
Get the Uzi weapon.

Weapon Master III - GamerScore 10:
Get the Shotgun weapon.

Easy Game - GamerScore 20:
Complete the game on Easy difficulty setting.

Medium Game - GamerScore 25:
Complete the game on Medium difficulty setting (this includes the Easy game achievement).

Slayer I - GamerScore 30:
Without dying defeat the T-Rex in Peru.

Slayer II - GamerScore 30:
Without dying defeat the Twin Centaur Bosses in Greece.

Slayer III - GamerScore 30:
Without dying defeat the Torso Boss at Lost Island.

Croft Manor Speed Run - GamerScore 30:
Complete the Croft Manor Time Trial.

Greek Speed Run - GamerScore 30:
Complete ALL the Greece Time Trials.

Egyptian Speed Run - GamerScore 30:
Complete ALL the Egypt Time Trials.

Peruvian Speed Run - GamerScore 30:
Complete ALL the Peru Time Trials.

Lost Island Speed Run - GamerScore 30:
Complete ALL the Lost Island Time Trials.

Good Show in Egypt! - GamerScore 35:
On your first attempt complete ALL the Egypt Super Actions without fail.

Good Show in Greece! - GamerScore 35:
On your first attempt complete ALL the Greece Super Actions without fail.

Good Show in Peru! - GamerScore 35:
On your first attempt complete ALL the Peru Super Actions without fail.

Good Show on Lost Island! - GamerScore 35:
On your first attempt complete ALL the Lost Island Super Actions without fail.

IRON Raider in Greece - GamerScore 35:
Without dying Complete Greece.

IRON Raider in Peru - GamerScore 35:
Without dying complete Peru.

IRON Raider in Egypt - GamerScore 40:
Without dying complete Egypt.

IRON Raider on Lost Island - GamerScore 40:
Without dying complete Lost Island.

Lost Island Tomb Raider - GamerScore 40:
Collect ALL the Artifacts and Relics in Lost Island.

Slayer IV - GamerScore 40:
Without dying defeat Natla in Lost Island.

Peruvian Tomb Raider - GamerScore 40:
Collect ALL the Artifacts and Relics in Peru.

Greek Tomb Raider - GamerScore 40:
Collect ALL the Artifacts and Relics in Greece.

Egyptian Tomb Raider - GamerScore 40:
Collect ALL the Artifacts and Relics in Egypt.

Hard Game - GamerScore 45:
Complete the game on Hard difficulty setting (this includes the Easy and Medium game achievements).