At the demo title screen highlight New Game and hold Right for a few seconds.
Double Ammo
Highlight Advanced Mode at the main menu, then press and hold Right until the word Advanced turns green.
Easier Advanced Mode
On the difficulty select menu highlight Advanced and hold Right for a few seconds
7/15/2005
Infinte Magnum Ammo in Advanced Mode
When you place the red jewel into the tiger statue, three cases of magnum ammo will be revealed for the taking. Take one (or two), leave the room, and then enter it again. All three cases will have respawned. Use this as many times as you like for infinite ammo.