In the year 2XXX, the Xiliens have declared war on the Earth for the second time and now have more monsters than before. The commander tells Earth to either surrender or be destroyed. The intro then goes on to either:
- Say that the player's monster broke free from the Antarctic and the fate of Earth now lies in it's hands. (Earth Defenders only)
- Say that Earth had no intentions of surrendering, knowing that they have defended Earth against Aliens in the past, and send the player's monster to defend Earth. (GDF only)
- Say that conquering Earth was hard for the Xiliens in the past, but the player's monster shows promise to achieve victory. They will test this monster and then send it to Earth to take over the planet. (Aliens only)
Later, the player's monster either attacks (Earth Defenders or GDF) or defends (Aliens) the Xillien's Earth Base in World Children's Land. After the player wins, the Xilliens either send the player's monster to Planet X to face their trump card (Earth Defenders or GDF) or send them to fight Godzilla in Tokyo (Aliens). The ending tells us that the player's monster saved the Earth (Earth Defenders or GDF) or took over the Earth for the Xilliens (Aliens).
Battle Mode is where 1 or 2 players can choose two monsters and battle against one another. The stats for Physical Attacks, Special Attacks, and Power Regeneration can be modified, with the default being 3, 1 being the lowest, and 5 being the highest.
The game has a total of 64 monsters (Counting the different versions and transformations), all of which are playable, although most have to be unlocked. In addition, some monsters can transform into different ones, either at will at the cost of some energy, or after a certain amount of life has been depleted and with enough energy. The playable characters are:
- Anguirus (1968)
- King Kong (1962)
- Manda & Gotengo (1963)
- King Ghidorah
- Baragon (1965)
- Ebirah (1966)
- Minya (1967)
- Kamacuras (1967)
- Kumonga (1967)
- Gorosaurus (1967)
- Hedorah (1971)
- Jet Jaguar
- Zone Fighter
- King Caesar (1974)
- Super Xs
- Zilla (Zilla Junior)
- Monster X
- Keizer Ghidorah
- M.U.T.O. (Female)
- Legendary Wolfman
- Glacies (Original Monster)
- Godzilla Junior
- Super X
- Super XIII
- King Ghidorah
To Be added
- Monster Island
- Planet X
- World Children's Land (Godzilla Tower)
- Mount Fuji
All stages except for Planet X have a day, noon, and night option in Battle Mode.
The following section shows the unlock codes for the monsters. If you wish to unlock the monsters normally and do not wish to cheat, please skip this section.
All codes must be entered in lower case. The codes for unlocking kaiju are:
- sollgel (Kamacuras)
- mysterians (Moguera)
- savetheearth (Hedorah 1971)
- monster0 (King Ghidorah 1964)
- mafune (Titanosaurus)
- erika (Biollante)
- serizawa (Destoroyah)
- leo (Mothra Leo 1996)
- heisei (Godzilla 1994)
- gino (Zilla)
- gorath (Monster X & Keizer Ghidorah)
- ghogo (Rainbow Mothra & Aqua Mothra)
- unbelievable (Varan)
- meganula (Megaguirus)
- eviltwin (Battra)
- unleashed (Krystalak)
- meltdown (Burning Godzilla)
- ichiro (Gabara)
- subterranean (Baragon 1965)
- exitium (Glacies)
- iceberg (Godzilla 1962)
- spacehunterm (Gigan 1972)
- seatopia (Megalon)
- spacemetal (Fake Godzilla & MechaGodzilla 1974)
- paris (Gorosaurus)
- tailslide (Godzilla 1973)
- organizerg1 (Godzilla 2000)
- millenian (Orga)
- atragon (Manda & Gotengo)
- azumi (King Caesar)
- goro (Jet Jaguar)
- ungcc (Garuda, MechaGodzilla 1993, & Super MechaGodzilla)
- fukuoka (SpaceGodzilla)
- sakimori (Zone Fighter)
- 8thwonder (King Kong)
- gmk (Godzilla 2001)
- srawlanif (Unlock all Silver Monsters)
- gojira54 (Godzilla 1954)
- tokyosos (Godzilla 2002)
- awm (Unlock all Gold Monsters)
- 1131954 (Unlock everything)
There are certain mechanics to the gameplay that will usually change the death of an enemy monster.
- If Godzilla 1954 is killed in battle, he will emit the death cry that he made in the original film before falling onto his back.
- If Mothra Larva is killed by a beam, an adult Mothra will fly in and attack the player. This ONLY works in Arcade Mode.
- Minya has different animations for each of his roars. If you defeat Gabara, the victory screen will show Minya dancing and shouting "Yayayaya!". Also, if you defeat Kumonga, the victory screen will show Minya dancing and shouting "How do you like that, weirdo?!". If he is defeated in battle, he will run away.
- If King Ghidorah 1991 is killed, he will fall on his back and roar. If he is hit by a beam attack during this, his middle head will fly off.
- If Mecha-King Ghidorah is killed with a beam attack, KIDS will rise out of the explosion and fly away.
- If M.O.G.U.E.R.A. is killed with a beam attack, it will charge at the enemy and explode on contact. If it is defeated by a melee attack, it's right arm will be blown off while M.O.G.U.E.R.A collapses.
- Godzilla 2002's victory animation has him getting struck by lightning, much like how he does during his intro at the start of Godzilla Against MechaGodzilla. Additionally, when being defeated, Godzilla roars, slumps forward, and collapses.
- If Gezora is killed in battle, he slumps forward and collapses, with Yog retreating from his body, much like how he does in his film appearance.
- If Godzilla 2014 is defeated in battle, he leans forward and breathes heavily, then collapses face-forward onto the ground, much like he did in his film appearance after defeating the female M.U.T.O.
- If M.U.T.O. (Female) is killed, she will lean forward for a second and then collapse like normal. However, if she is hit by a beam attack during this brief second, her head will be decapitated, much like how she was when Godzilla performed the "Kiss of Death" on her in her film appearance.
By pressing "Shift," alternate costumes can be selected. However this only works for Godzilla 1954, Godzilla 2002, and Female M.U.T.O.
- Godzilla 1954's alternate costumes include:
- Black and White Palette Swap
- Grey with Blue Fire
- Grey with White Fire
- Grey with Orange Fire
- Brown with Blue Fire
- Brown with White Fire
- Green with Orange Fire
- Godzilla 2002's alternate costume is his 2003 incarnation, including his battle scar from when he was injured by Kiryu's Absolute Zero Cannon. Additionally, both incarnations possess different Heat Ray charging animations.
- Female M.U.T.O.'s alternate costume is her when she is pregnant. She carries around her Egg Sack on her chest.
- Once the arcade mode is completed while playing as Godzilla 1954, the end message reads "In the end, the people of Planet X could not defeat the monster. They had no choice but to return it to Earth and admit defeat. The Earth, and the entire galaxy, was safe once again thanks to Godzilla... or is it?" as a picture of Godzilla 1954 pops up over the Earth.
- Battra was originally a part of the game when it was fully released, but only in his Imago Form. However on Halloween 2014, his character was completely revamped, with a new character model and set of attacks, as well as his Larva Form as a playable character.
- In celebration of Godzilla's 60th anniversary, on November 3rd, 2014, when the game is beaten in arcade mode, a slideshow of sceenshots recreating each of the films' most iconic moments is shown with the intro music from Godzilla: Final Wars playing. At the end of the slideshow, an outline of Godzilla 2014 is shown and his roar can be heard. This ending can only be accessed if you unlock every character in the game.