BIG HEAD MODE
[Submitted by: cheatmaster113 ]
Enter the following cheat in the load game menu.
left,up,left,up,right,down,up,right,left.

then the screen should flash if the cheat was entered correctly

Unlock all cybertron missions
[Submitted by: cheatmaster113 ]
Enter this code at the new game screen. right,up,up,down,right,left,left.

Cheat Code List
Enter cheat codes listed below from the menu that has campaign and bonus features listed:

Down, Up, Left, Right, Right, Right, Up, Down	Unlock All Mission
Up, Down, Left, Right, Up, Up, Down	Infinite Ammo.
Down, Down, Up, Up, Right, Right, Right	Robovision Optimus Prime skin
Right, Down, Left, Left, Down, Up, Up	Starscream G1 skin
left, up, down, down, left, up, right	Jazz G1 skin
Right, Left, Right, Left, Right, Left, Right	No vehicle's running on the street and no tank's/cop's attack
Right, Up,Up,Down, Right, Left,Left	Unlocks Bonus Cybertron Autobot And Cybertron Decepticon Missions.
Down, Left, Left, Down, Right, Right, Up	G1 Megatron
Up, Up, Down, Down, Right, Right, Right	G1 Optimus Prime