Godzilla: Destroy All Monsters Melee

Unlock Godzilla 2000:
To unlock Godzilla 2000, complete Adventure mode with Godzilla 90's

Unlock Destroyah:
To unlock Destroyah, complete Adventure mode with Godzilla 2000.

Unlock Gigan:
To unlock Gigan, beat Adventure mode with Aguirus.

Unlock King Ghidorah:
To unlock King Ghidorah, beat Adventure mode with Megalon.

Unlock Mecha-King Ghidorah:
To unlock Mecha King Ghidorah, beat Adventure mode with King Ghidorah.

Unlock Mecha-Godzilla:
To unlock Mecha Godzilla, complete Adventure mode with Destoroyah, Rodan and Mecha-King Ghidorah.