The easy way out of level 1:
Activate the all weapons cheat then go to the room with the mud.
Walk through the mud and as Lara is just about to die use a large med pack.
Repeat this process until you have reached the other side, get the key and you've practicaly finished the level.
More tricks, tips and cheats for this game are right here - Tomb Raider III: Adventures of Lara Croft cheats
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