Transformers: The Game [PSX] (2007)

Play as Optimus Prime Generation 1 version:
Press Up(2), Down(2), Right(3) at the "New Game" main menu. The screen will flash to confirm correct code entry. Select the "Bonus Features" option then the "Generation 1" option to use the new appearance.

Play as Starscream Generation 1 version:
Press Right, Down, Left(2), Down, Up(2) at the "New Game" main menu. The screen will flash to confirm correct code entry. Select the "Bonus Features" option then the "Generation 1" option to use the new appearance.

Play as Jazz Generation 1 version:
Press Left, Up(2), Down, Left, Up, Right at the "New Game" main menu. The screen will flash to confirm correct code entry. Select the "Bonus Features" option then the "Generation 1" option to use the new appearance.

Bonus Cybertron missions:
Press Right, Up(2), Down, Right, Left(2) at the main menu and start through replay missions. The screen will flash to confirm correct code entry.

Generation 1 Megatron:
Collect all the Transformer Shields in the Decepticon story line.

Generation 1 Optimus Prime (cartoon model):
Collect all the Autobot Faction Symbols in the Autobot story line.

Generation 1 Robo-vision Optimus Prime:
Successfully complete the Autobot story line.