At the main menu, hold L + R and press Up(2), Down, Up, A, X, A, B, Up, Down, Y, Start. Note: Use the D-pad. If you entered the code correctly, you will hear a song. You will become invincible with infinite ammunition.
Collect all artifacts in the game to unlock an art gallery.
Press R as before you hit the ground to enter combat mode. You will not get any damage from falling.
Press X button to pistol whip your adversary. Note: This works for all guns, not just the pistols.
To drink from the canteen, hold A. If you instead tap A, it will take longer. Holding A also helps when you fill your canteen.
In the level where you start out in a room enclosed by a vine door, cut the door and walk forward. It should start a short intermission sequence of Indy running towards a little window. Skip through it and when it is over, select the whip and jump. While in the air press A. If done correctly, you should now be swinging above a courtyard. Swing to the other side and continue the mission.
Equip the PaCheng and press R to block.
When you reach Istanbul Sunken City, to break the damaged wall, hover above the head in the water with the crane. Press A and it will automatically break it up.