To unlock an alternate ending as any of the Earth Defenders or GDF monsters, acquire all of the seven Power Surges. You will receive the "Tyrant" ending (instead of the "Hero" ending) upon completing Story mode.
Bonuses
Successfully complete the game with Godzilla to unlock the following bonuses.
Concept Art: Pictures 1 through 24.
Levels :London, Monster Island, Mothership, New York, Seattle, Tokyo.
Monsters: Baragon, Battra, Mecha King Ghidorah, Mechgodzilla2, MegaGurious, Methra, Moguera, Obsidius, Orga, Space Godzilla, Godzilla 1990, Jet Jaguar.
Video: Trailers, Video 1, Video 2.
Cheat mode
Press X + Up to display the cheat entry screen. If that does not work then finish a characters story and go to continue. Then, skip the animation and hold X.
Display HUD
Enter 858585 as a code.
Easy points
Fight a two player battle in Brawl mode. You will earn has much as 1,000 points to spend in the store. This helps unlock more characters faster than playing through Story mode multiple times.
Hide HUD
Enter 585858 as a code.
Power surge attacks
After activating any of the various Power Surges, press Square + Circle to unleash a Power Surge attack. These attacks vary from each of the seven Power Surges (each Power Surge attack is a variant from Godzilla 90's Nuclear Pulse RAGE attack from Godzilla: Save The Earth). Note: Due to a glitch, the Power Surge attacks may or may not do any damage to enemies when used.
Power Surges
You can acquire Power Surges by defeating any monster that is under the influence of Power Surge crystals (the monster will be using a Power Surge). To activate any of the acquired Power Surges, press Square + Circle at any time during a battle. Each Power Surge can only be used once per battle. Also, the Power Surge used will be random. Note: Power Surges can only be used in Story mode.
Set day
Enter 0829[XX] as a code. Note: [XX] is Day 0-based. For example, entering 082910 would take you to Day 11 of the saved game you are currently playing. This code only works after you have started a saved game.
Show Monster moves
Enter 411411 as a code. Moves will appear under the HUD.