Faction unlock
Alien
Requirements: None
Price: 12,000

Global Defense Force
Requirements: None
Price: 5,000

Mutants
Requirements: Beat Story Mode
Price: 15,000

Character unlock
Baragon
Requirements: Using the Alien faction, play "Friend in Need" at Monster Island. On the isle, simply free Baragon from the influence of the crystals and complete the stage. Afterwards, play the "Baragon" stage at Monster Island and defeat the creature to add him to the shop.
Price: 15,000

Biollante
Requirements: Using the Earth Defenders, play the "Rumble in the Surf" at Tokyo. In the arena, there should be a building with a glowing green base and vines wrapped around it. Destroy this structure to have Biollante briefly emerge and then disappear. After beating this level, select the stage "Biollante" at Tokyo next, and beat the genetic monster to be able to purchase her at the shop.
Price: 30,000

Godzilla 1954
Requirements: Have all other monsters, save Godzilla 1990s, available at the shop or have a certain amount of playtime registered on the game (exact figure unknown at this time).
Price: 100,000

Godzilla 1990s
Requirements: Buy at least one monster from each faction or beat the game with each faction.
Price: 20,000

Jet Jaguar
Requirements: Unlock Global Defense Force Faction
Price: 30,000

King Caesar
Requirements: None
Price: 10,000

Krystalak
Requirements: Using the Alien faction, play the "Terran Mind-Control" level at New York. In the metropolis, destroy a large crystal structure with odd rock plates at the base that is found in the crater. Much later (around nine days after), the "Rise of Krystalak" stage will appear at New York and after selecting it and beating the monster the crystal creation will be added to the shop.
Price: 20,000

Mecha-King Ghidorah
Requirements: Using the Earth Defenders, play the "Invasion" at San Francisco. In the level, which features the Mothership looming overhead, simply defeat King Ghidorah. After this victory, select "M.K.G." at San Francisco and beat Mecha-King Ghidorah to be able to purchase the cyborg creature. It should be noted that since you have to face King Ghidorah in
the "Invasion" level the player must select a character from the Earth Defenders that will allow this confrontation to happen, such as Anguirus or Baragon.
Price: 50,000

Mechagodzilla
Requirements: Unlock Alien Faction
Price: 25,000

Mechagodzilla 2
Requirements: Unlock Global Defense Force Faction
Price: 15,000

Megaguirus
Requirements: Using the Earth Defenders, play the "Enter General Gyozen" stage at London. At the city, destroy three giant light teal crystals. Once this is complete, near the end of the game, after the Atoragon is defeated, the "Wrath of Megaguirus" stage will appear at London. Select this and simply beat the monster to add it to the shop. Note: the "Enter General Gyozen" stage does not actually say "reveal a new monster".
Price: 20,000

Moguera
Requirements: Unlock Global Defense Force Faction
Price: 5,000

Mothra
Requirements: None
Price: 10,000

Obsidius
Requirements: Using the Global Defense Force Faction, play the "Big Trouble" stage at Seattle. At the volcanic area, destroy the two cone shaped crystals down where the lava meets the water then complete the level. Afterwards, select "Birth of Obsidius" at Seattle and defeat the monster to add him to the shop.
Price: 20,000

Orga
Requirements: Unlock Alien Faction
Price: 50,000

SpaceGodzilla
Requirements: Using the Mutant Faction, collect at least four Power Surges and then beat the "Tyrant" level at the end of the game. This will add SpaceGodzilla to the shop.
Price: 100,000

Titanosaurus
Requirements: Using the Global Defense Force Faction, play the "Soloist" stage at Sydney. On the frozen land, destroy three circular "cake-shaped" ice structures that appear just outside the force field, meaning a beam will have to be used. After the ice structures are destroyed, and the level cleared, play the "Awakening Titanosaurus" level at Sydney and defeat the dinosaur to add him to the shop.
Price: 25,000

Varan
Requirements: Using the Alien Faction, play the "On the Mothership " level. On this stage, destroy all three purple structures on the wall. This will be fairly difficult, as each must be destroyed by the player's beam at a range where it's hard to tell if it was actually destroyed or not until backing away. Once this task is done, and the level beaten, select "Evicting Varan" on the Mothership level and defeat the creature to add him to the shop.
Price: 30,000

Stage unlock
London
Requirements: None
Price: 15,000

Monster Island
Requirements: None
Price: 10,000

Mothership
Requirements: Either blast down the ship in the "Invasion" at San Francisco stage and select the Mothership as the next stage choice, or play as the Alien faction and select the level after one of the other factions has taken down the vessel. After either of these events, the stage should be available for purchase.
Price: 35,000

New York
Requirements: None
Price: 30,000

Seattle
Requirements: None
Price: 25,000

Tokyo
Requirements: None
Price: 20,000

Opening Cheat Menu
To open the cheat input area, simply press A and up on the directional pad on the remote at the same time while Story mode is highlighted on the main menu.

Codes
Toggle Game Version Number: 787321
Set Day in Story Mode: 0829XX
The "XX" is the exact day you want +1. So 09 would generate a result of Day 10. Please note that you must have started a save game already for this to work.
Add 90000 store points: 031406
Show Monster Moves: 411411
Unlock All: 204935