Godzilla, a gigantic creature from underneath the sea, has been both the bane and the savior of Earth. Godzilla's power is so feared that scientists have begun experimenting on it's DNA and creating artificial G-Cells of the monster's power. A group of aliens, named the Vortek decide to invade the Earth to take away G-Cells created using Godzilla's DNA. They do this by controlling various other gigantic monsters, who will battle amongst themselves. Only a monster with free-will would be able to destroy the Vortek's army and drive away the Vortek.

Godzilla: Save the Earth is a 3-D Fighting game, somewhat of a sequel to Godzilla: Destroy All Monsters Melee. Players choose from among 18 monsters, previously seen in Godzilla movies, with which to engage in battle and destruction. The roster includes: Godzilla (1990's version & 2000's version), Mecha-Godzilla (version 2 & version 3), Spacegodzilla, Anguirus, Destoroyah, Gigan, Moguera, Jet Jaguar, Baragon, Rodan, Megalon, Megaguirus, Mothra (in larval & adult forms), Orga, King Ghidorah and Mecha-King Ghidorah. Each monster comes with a variety of punches, kicks, grabs, throws, blocks and ranged attacks. In addition, each monster has a variety of unique moves activated by combinations of buttons. Many monsters can even fly. Power-Ups can be found that restore health, restore energy, activate Rage mode and target the enemy for Air Strikes.

There are a variety of game modes: Action, Versus, Survival, Challenges and Melee. During Action mode it's one monster against a number of monsters in 1vs1 combat, the number of monsters to be fought dependant on the difficulty settings. Action mode also features mini-challenges such as Bowling, Demolition, Osaka crunch, Rail Shooter, Vorillium Basket Ball, Mother Ship, Protect the Tower, Destroy the City (percentage), Destroy the City (point value), Attack the Navy and more. Many of these are unlocked in the Challenges mode after encountering them. Success in the Action mode (or by picking up G-cells) awards the player with points to unlock Gallery Photos, Arenas and new characters. Versus mode is the multiplayer version of Save the Earth. Survival Mode. Melee mode also feature multiplayer and is a 4-person free-for-all of monster mayhem in a small, contained arena.