To unlock all missions for both the Autobots and Decepticons, insert the following code at the game’s main menu (where the campaign options are listed, et cetera): Down, Up, Left, Right, Right, Right, Up, Down.

To unlock the following skins, fulfill the corresponding condition in the game…

G1 Jazz - Complete all sub-missions (both campaigns)

G1 Megatron - Acquire all Decepticon icons

G1 Optimus Prime - Acquire all Autobot icons

G1 Starscream - Finish the Decepticon campaign

Robovision Optimus Prime - Finish the Autobot campaign

To unlock the following, insert the passwords on the main menu (where campaigns can be selected, et cetera)…

G1 Jazz Skin - Left, Up, Down, Down, Left, Up, Right

G1 Megatron Skin - Down, Left, Left, Down, Right, Right, Up

G1 Optimus Prime Skin - Down, Right, Left, Up, Down, Down, Left

G1 Starscream Skin - Right, Down, Left, Left, Down, Up, Up

No Vehicles, Military, or Police - Right, Left, Right, Left, Right, Left, Right

Robovision Optimus Prime Skin - Down, Down, Up, Up, Right, Right, Right

Unlock All Missions - Down, Up, Left, Right, Right, Right, Up, Down

Unlock both Cybertron Missions - Right, Up, Up, Down, Right, Left, Left

Unlock Unlimited Ammo - Up, Down, Left, Right, Up, Up, Down

Unlock Unlimited Health (Invincibility) - Left, Left, Up, Left, Right, Down