Enter the following codes during gameplay (preferably when you are not near enemies) to enable the corresponding effect. The Bulletproof Lara, Draw Enemy Health and One Shot Kill codes will only work if the game has not been patched with the 'Title Update 2'. If you enter a code correctly you will hear a confirmation sound.
Bulletproof Lara Hold LT and press A, RT, Y, RT, X, LB.
Draw Enemy Health Hold LT and press X, B, A, LB, RT, Y.
One Shot Kill Hold LT and press Y, A, Y, X, LB, B.
Level Clear Hold LT and press Y, click the Left Analog-stick, press B, RB, X.
Nuclear Wave Hold LT and press X, Y, RB, A, B, LB, X. Then hold RT and press LB during gameplay to emit a nuclear wave.
Swim Dart Hold LT and press A, RB, LB, RT, X, Y. Execute the swim faster move while swimming to activate the code.
Stage Section Clear Hold LT and press RB, Y, A(2), B, RB.
The followng 3 'Tomb Raider: Legend' codes will work on 'Tomb Raider: Underworld'. To enter the code hold the Left Trigger during gameplay and input the desired code. If the code has been entered correctly you will hear the 'Checkpoint' sound as confirmation.
Invincibility: Hold the Left Trigger and press A, RT, Y, RT, X, LB
One Shot Kill: Hold the Left Trigger and press Y, A, Y, X, LB, B
Show Enemy Health Numerically: Hold the Left Trigger and press X, B, A, LB, RT, Y
The following features can be unlocked by completing the indicated task.
Unlock White Swimsuit: This outfit which is for use in the Mediterranean Sea level becomes available when you complete the game.
Unlock Treasure Hunt Mode This feature becomes an available option at the 'Main' menu when you clear the game on any level. In Treasure Hunt mode you replay the game without having to complete the puzzles to collect the missing treasure.
Unlock Storyboards: Complete the game on the Master Survivalist difficulty setting.
Unlock Lara Croft Concept Art: Collect ALL the Relics.
Unlock Creature Concept Art: Collect ALL the smaller treasures in each level.