While playing a game, type "debugon" to enable debug mode. Then, dinosaurs will ignore your character until you shoot, weapons will have infinite ammunition, and lava is not harmful. Additionally, enter one of the following codes to activate the corresponding cheat function:

Run very fast [Ctrl]
Longer jumps [Ctrl] + N
Toggle slow motion [Shift] + S
Toggle frame rate and polygons per frame display [Shift] + T
Full map [Tab]