Transformers: The Game Codes -

Unlimited health
Press x2, , , , , at the menu with the "Campaign", "Bonus", and "Options" selections. The screen will flash to confirm correct code entry.

Ammo no reloaded
Press , , , , x2, at the menu with the "Campaign", "Bonus", and "Options" selections. The screen will flash to confirm correct code entry.

Bonus Cybertron missions
Press , x2, , , x2 at the menu with the "Campaign", "Bonus", and "Options" selections and start through replay missions. The screen will flash to confirm correct code entry.

Play as Optimus Prime Generation 1 version
Press , , , , x2, 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 Starscream Generation 1 version
Press , , x2, , x2 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 , , x2, , , 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 , x2, , x2, 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.

Achievements
Complete each achievement to get the allotted gamerscore:

Keeper of the AllSpark (75) - There is no Transformer that stands greater than you. You have achieved 100% completion.
Mad Skillz (40) - You are skilled beyond belief. Achieved all Skill items on all levels.
Pride of Brawl (15) - Your destruction comes naturally as a Decepticon. Achieved full Destruction Skill.
Pride of Bumblebee (60) - You've scouted the world thoroughly. All the secret icons have been collected.
Pride of Ironhide (15) - You are the epitome of an Autobot. Achieved full Heroic Skill.
Pride of Megatron (20) - 200 Autobot Drones have fallen before you.
Pride of Optimus Prime (20) - 200 Decepticon Drones have met their match.
Robots in Disguise (25) - You've transformed 500 times.
Root of all Evil (15) - You take pride in destroying your enemies. Achieved full Evil Skill.
Shot Putter (15) - You've sent objects flying. Achieved full Throw Skill.
Sideways Motion (15) - You can handle turns with ease. Achieved full Slide Skill.
Speed Demon (15) - You've really burned rubber. Achieved full Speed Skill.
Transform and Roll Out (10) - You've transformed for the first time.
We Don't Need Roads (15) - Who needs roads when you can fly through the air? Achieved full Jump Skill.
What Challenge? (10) - You have handled a challenge with ease. Complete your first Challenge sub-mission.
Wrong Way! (15) - You're living dangerously. Ram 250 Cars.

Secret Achievements
Additionally there are 26 secret achievements:

Suburban Hero (25 points) - Bumblebee protects Sam in The Suburbs.
Suburban Hero Challenger (20 points) - Complet all challenge sub-missions in The Suburbs.
Neighborhood Watch (25 points) - Continue your defense of The Suburbs as Jazz and Optimus Prime.
Neighborhood Watch Challenger (20 points) - Complete all challenge sub-missions in the suburbs.
Could You Describe the Ruckus? (25 points) - Bumblebee causes a disturbance in order to escape the Hoover Dam with the AllSpark.
The Ruckus? Challenger (20 points) - Complete all challenge sub-missions in Inside Hoover Dam.
Downtown Defender (25 points) - The Last Stand has been made. There's only one thing left to do.
Downtown Defender Challenger (20 points) - Complete all challenge sub-missions in Autobot City.
Look to the Stars (50 points) - Megatron and the Decepticons are finished.
Sand Blaster (25 points) - Qatar is destroyed.
Sand Blaster Challenger (20 points) - Completed all challenge sub-missions in Qatar Desert.
Suburban Scourge (25 points) - The Autobots fall before you. The Suburbs are done for.
Suburban Scourge Challenger (20 points) - Completed all challenge sub-missions in The Hunt for Sam Witwicky.
Air Traffic Destroyer (25 points) - Starscream's power knows no bounds. The airbase's defenses are obsolete.
Air Traffic Destroyer Challenger (20 points) - Complete all challenge sub-missions in the Airbase.
Downtown Demolisher (25 points) - The city is in ruins. There's only one thing left to do.
Downtown Demolisher Challenger (20 points) - Complete all challenge sub-missions in the Decepticon City.
Finish this Planet (50 points) - Optimus and the Autobots are but a memory. Earth is yours.
Weapon Systems Inactive (20 points) - Complete Suburbs Chapter 1 using only melee attacks.
Sharp Shooter (40 points) - Complete Airbase Chapter 3 with more than 2:30 minutes remaining.
Turbo? We don't need no turbo! (30 points) - Complete Hoover Internal Chapter 2 without using boost.
Land Shark (10 points) - Spend 2 minutes underground.
Batter Up (10 points) - Find a bat and make your enemy fly.
Pit Crew (10 points) - Use a large tire to harm your enemy.
Ring-A-Ding-Ding (10 points) - Use the Helio phone as a weapon.
I know Kung-Fu (30 points) - Perform 1000 punches.

Defeating the cement truck Decepticon
When you are fighting the cement truck Decepticon as Ironhide, to knock him down transform and run him over. Then, pick him up and throw him.