Primal Cheats

Code menu:
Press and hold L1 + L2 + R1 + R2 for about five seconds in the main menu or bonus materials menu to see the code entry screen.

Primal in bonus materials:
Submit the code OBLIVION in the code entry screen to get BONUS E. Other bonus features include a BEHIND THE SCENES VIDEO featuring the voice actors for the two protagonists, which can also be unlocked by gathering hidden items while playing the game.

Concept art:
By gathering the various Tarot Cards in the game to unlock concept art. You can see the art after the first part of the game is finished. 
User Cheat by LinkinParkDreams

Gameplay Hints:
Unlike most action adventure titles where fighting enemies is important, in Primal you will need to focus on figuring where to go next, getting there, and getting beyond whatever obstacles that inhibit passage. Most of these obstacles are locked door and door-like devices which need to be unlocked using teamwork.
User Cheat by LinkinParkDreams

While playing as Jen, if you don't know what to do you can always push Triangle and ask Scree for advice. For most of the game Scree's advice will keep Jen on the right track.

Selecting characters:
Gamers will need to utilize both characters (Jen and Scree) in order to complete stages. Certain tasks can only be accomplished by a certain character. 

Scree can walk past beasts and other threats that would normally attack Jen if gamers selected her first. Scree can also turn himself into a solid rock to slip past guards and he can climb some stone walls. More importantly he can inhabit intricate stone statues so you can solve puzzles.

Jen is mainly effective during combat sequences and solving puzzles later in the game. She can absorb the traits of 4 specific races of Oblivion. She can have super strength, breathing under water, etc when taking on different forms. If you lose the life force of a particular race, Scree can absorb the energy needed to give Jen a Power-Up.

Code menu:
Press and hold L1 + L2 + R1 + R2 for about five seconds in the main menu or bonus materials menu to see the code entry screen.. Now highlight one of the "A" letters in a code, then press and hold X and push Left or Right to change it. Push Square to accept the finished code. Push Triangle to exit the code entry screen.
Invulnerability: MONSTROUS
Solum scenes: Unknown
Aquis scenes: Unknown
Aetha scenes: Unknown
Volca scenes: Unknown
Tarot Gallery: Unknown
Easy Kill: DEAMONISE
Bonus A: Unknown
Bonus B: PRIMAL
Bonus C: DEMONREALMS
Bonus D: MORTALIS
Bonus E: OBLIVION

Code menu (Collectors and PAL versions):
Use one of the codes below for the Collectors and PAL versions of the game.
Invulnerability: DEMONISE
Solum scenes: SNOWFLIGHT
Aquis scenes: CHARYBDIS
Aetha scenes: FLINTLOCK
Volca scenes: SUNSTONE
Tarot Gallery: ARCANUM
Easy Kill: MORTIFIC
Bonus A: SEABREEZE
Bonus B: AURORA
Bonus C: PSYCHOSIS
Bonus D: MIRRORY
Bonus E: ASCENDENT

Code menu (beta version):
Use one of the codes below for the beta (unreleased) version of the game. Cheats: JEN
Solum scenes: SOLUM
Aquis scenes: AQUIS
Aetha scenes: AETHA
Volca scenes: VOLCA
Tarot Gallery: TAROT
Easy Kill: EASYKILL
Bonus A: BONUSA
Bonus B: BONUSB
Bonus C: BONUSC
Bonus D: BONUSD
Bonus E: BONUSE

Actors featurette FMV sequence:
After finishing the Solum realm you will unlock the "Actors Featurette" option.

Making of FMV sequence:
After finishing the Aquis realm you will unlock the "Making Of" option.

Programmer interview FMV sequence:
After finishing the Aetha realm you will unlock the "16 Volt Interview" option.

Trailer FMV sequence:
After finishing the Volca realm you will unlock the "Trailer Video" option.