In Celyon, 2nd level (hunters camp) when you drop the box off the ledge that is tied by rope, there is an artifact in there.

Press R as before you hit the ground to enter combat mode. You will not get any damage from falling.

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.

Hold L + R and press Up(2), Down, Up, A, X, A, B, Up, Down, Y, Start at the "Press Start" screen. Note: Use the D-pad. A song will confirm correct code entry. You will become invincible with unlimited ammunition.

On the first level go to the water fall and go behind it and you will find the first artifact of the game.

Go to the start screen and HOLD L+R and press Up,Up,Down,Up,Down,Y,Start!

Go into combat mode before you hit the ground and you can jump from any height without hurting yourself.

Pause game play and look carefully at Indy to notice that his hat is gone. Look at his forehead during game play, then and look back at his forehead.

Press X button to pistol whip your adversary. Note: This works for all guns, not just the pistols.

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.

Find all artifacts in the game.