Type "debugup" during game to activate Debug mode. (Your character will become impervious to lava, gain an unlimited supply of ammunition, and will be undetected by dinosaurs – until then have been shoot at.) Additional Debug features are activated by pressing the following key combinations.

Effect         Hotkey
Longer jumps   [Ctrl] + N
Fast motion    [Ctrl]
Full map       [Tab]
Slow motion    [Ctrl] + S
Swim *         [Space bar]

* Press [Space bar] before entering water.