No traffic, police, or military:
Press Right, Left, Right, Left, Right, Left, Right at the menu with the “Campaign”, “Bonus“, and “Options” selections. The screen will flash to confirm correct code entry. The only vehicles remaining will be parked.

Play as Optimus Prime cartoon Generation 1 version:
Press Up, Up, Down, Down, Right, Right, 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.

Play as Optimus Prime Generation 1 version:
Press Down, Right, Left, Up, Down, Down, Left at the menu with the “Campaign”, “Bonus“, and “Options” selections. 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 Robovision Optimus Prime:
Press Down, Down, Up, Up, Right(3) at the “New Game” main menu. The screen will flash red to confirm correct code entry. Go the “Bonus Features” option then the “Generation 1″ option to select “Robovision Optimus”

Play as Starscream Generation 1 version:
Press Right, Down, Left, Left, Down, Up, Up 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, Up, 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.

Play as Megatron Generation 1 version:
Press Down, Left, Left, Down, Right, Right, Up at the menu with the “Campaign”, “Bonus“, and “Options” selections. The screen will flash to confirm correct code entry. Select the “Bonus Features” option then the “Generation 1″ option to use the new appearance.

Ammo no reloaded:
Press Up, Down, Left, Right, Up, Up, Down at the menu with the “Campaign”, “Bonus“, and “Options” selections. The screen will flash to confirm correct code entry.

All missions:
Press Down, Up, Left, Right, Right, Right, Up, Down at the menu with the “Campaign”, “Bonus“, and “Options” selections. The screen will flash to confirm correct code entry. All missions including the two special missions will be unlocked.

Bonus Cybertron missions:
Press Right, Up, Up, Down, Right, Left, Left at the menu with the “Campaign”, “Bonus“, and “Options” selections and start through replay missions. The screen will flash to confirm correct code entry.

Originally from CheatHappens