The games contained in the trilogy are based on the NA PS1 version of the game. As such, cheat codes match the original version's.

For the sake of the guide, I will refer them to the PS1 inputs - to enter the code, you will need to match the input.

For Playstation controllers, inputs will match, but for other controllers, you'll need to match the cardinal location of the inputs - for example, Square is X on an Xbox controller.

For keyboard, match the input (Square is Tongue so use the tongue input). I strongly recommend using a controller.

Here is a PS1 controller for reference :

There is no password system in the trilogy. As such, only "input" cheat codes function.

Pause Menu cheats

To enter these cheats, press pause, and while paused, press R1, hold it, and enter the corresponding sequence.

Electricity power-up : Right, Left, Right, Circle,Triangle, Right, Circle, Down, Right
Ice power-up : Circle, Circle, Left, Down, Circle, Up, Right
Fire power-up : X, up, Right, Up, Right, Right
Max Lives : Up, Circle, Triangle, Down, Right, Square, Down
Instant Speed : Down, Start, Right, Right, Down, Up
Invincibility : X, Square, Down, Down, Up, Down, Right
Super Jump : X, Circle, Up, Up, Down, Right, Right


Level Select

In the Dome, hold R1 and while holding it, press Select, X, Square, X, Right, Up, Left, Circle, Circle, Down, Down. This will open the level select menu. This does not include Planet X levels.

In the Dome, hold R1 and while holding it, press Select, Circle, Start, Right, Up, Square, Left, Left, Up, Start. This will unlock every world. This unlocks every TV channel and allows you to enter them. Does not include Planet X, as you need to collect the special remote.

To get to Planet X, you can use the level select, choose the bonus levels, clear them and then rinse and repeat.

Similarly to Gex 1, there is no password system in this game, meaning some passcodes cannot be entered.

If there is a way to input them, I will update this guide, but it means the bonus ending and remote cheat codes will not work. If a way is discovered to make the menu work, I will update this guide.

Pause Menu cheats

To enter these cheats, press pause, and while paused, press L2, hold it, and enter the corresponding sequence.

Debug Mode : Left, Circle, Up, Down, Right, Right, Left, Triangle, Up, Down
Infinite Lives : Up, Up, Down, Right, Triangle, Down
Invincibility : Left, Right, Triangle, Down, Right, Left
Level Select : Right, Right, Left, Right, Triangle, Down, Right. Press select after the code is entered.
Rambling Gex : Down, Right, Up, Down, Right, Left, Right, Down, Down
Stage Timer : Right, Triangle, Right, Left, Triangle, X. This makes a timer appear for stages.
Voice Activation Mode : Triangle, Left, Circle, Up, Down. Press select after the code is entered, it will make Gex speak.

Pause Menu cheats

To enter these cheats, press pause, and while paused, press L2, hold it, and enter the corresponding sequence. You will hear a prompt to confirm you entered the code.

Blabbermouth Gex : Down, Right, Left, Circle, Up, Right. Press select to hear him talk during gameplay.
Debug Menu : Up, Circle, Right, Up, Left, Right, Down. Afterwards, press Select when playing.
Invincibility : Down, Up, Left, Left, Triangle, Right, Down.
Level Select Menu : Left, Triangle, Up, Down, Right, Right. Afterwards, press Select when playing.

Password Codes

Unlike 1 & 2, passwords can be used in Gex 3. They are used in the vault, accessible once you beat the four secret levels. This guide only covers the cheat codes, but since you need a few extra steps for these, here's a bit of guidance :

Braveheartless : In Lake Flaccid. When climbing up to the bridge leading to the Western Station TV, the first mine Gex comes across contains the entrance to the secret level.
Dial "A" for Arson : In Mission Control, hit the three super computers. It opens a secret passage to it.
Cheesy Rider : Just outside to the left of Gangster TV's entrance in Funky Town.
The Abyssmal : On the way to Fairytales TV in Slappy Valley. When coming across a pool of water, look to the left in an alcove.

Now, the actual codes. Enter the codes on the terminal - it uses symbols :

Eight Hit Paws : Square, Diamond, Triangle, Triangle, Star, Diamond
Extra Life : Triangle, Circle, Star, Square, Square, X
Invincibility : Square, Star, Triangle, Square, Triangle, Diamond
Level Select : Square, Circle, Circle, Triangle, X, X
Play as Alfred the turtle : Square, X, Triangle, Square,Star, Star
Play as Cuz the dino : Square, Diamond, Square, Square, Triangle, Diamond
Play as Rex the dino : Square, Star, Star, Square, Triangle, Triangle
Talking Gex : Square, Triangle, X, Star, Square, X. Press select while playing to make him talk.
Ten Extra Lives : Square, X, Circle, Circle, Triangle, Square
Turn Off Timer : Square, Square, Diamond, Circle, X, X. Option can be found in the extras menu.
View All Videos : Star, X, X, Circle, Square, Triangle
View the Army video : X, Diamond, Star, Triangle, Triangle, Circle
View the Gangster video : Circle, Triangle, Square, Star, Diamond, Star
View the Western video : Diamond, Star, Square, X, Triangle, Circle

It sucks that we can't use passwords, and that the debug menu could screw up your current "save". Thanks LimitedRunGames!

If there are any inaccuracies, please tell me so I can fix it. Enjoy the games!