Open All Levels
Enter the code "SELLOUT" and then press "Start." This code will open up every level in the game, allowing you to access any level without beating them first.
Invisibility
The "SLLEWGH" code will provide invisibility, making Turok impossible to see by normal enemies. However, certain dinosaurs, such as the Tyrannosaurus boss, will still be able to see you.
All Weapons
Use the code "TEXAS" for All Weapons. It will give you every weapon available for the level you're playing. For example, it will not enable you to use the Gravity Gun on the first level because that weapon is not available until later levels.
Unlimited Ammo
The code "MADMAN" will give you unlimited ammunition for any weapon you have on your person.
Invincibility
For invincibility, type in the "EMERPUS" code, which will make you impervious to gunfire and drowning. You can still die in the flying levels by crashing your pterosaur into a wall or falling from large heights.
Big Heads
The Big Head code is "HEID." This will give all of the enemies, except besides dinosaurs, abnormally large heads, making them easier targets.
Hidden Zoo
Enter the code "ZOO" to be transported to a hidden level. In this level, all of the dinosaurs and other prehistoric animals in the game are in enclosures, which you can enter. All of the animals are killable with a provided war club. You can exit the Zoo at any time by pressing "Start" and then "Exit."
Demo Mode
Enter the code "HUNTER" to unlock a special demo mode, which allows you to play through the demo level presented to gamers before the game's release. It also allows you to control a pointer on the main title screen using the directional pad and pressing the fire button, Use the pointer to shoot passing animals and dinosaurs that run underneath the menu options on the screen.
Master Code
Enter the code "FMNFB" to unlock every cheat in the game, which you can toggle on or off at the Cheats screen.