| Unlockable: | How to Unlock: |
| Any playable character | Defeat Monster Island, The Final Battle level with that character |
| Atorgon | Defeat Atlantis Rises From The Deep level |
| Baragon | Defeat Hedorah Terrorizes San Francisco level |
| Biollante | Defeat Biollante Attacks Paris level |
| Destoroyah (NPC) | Defeat Monster Island, The Final Battle level |
| Ebirah | Defeat Ebirah Swamps Tokyo level |
| Hedorah | Defeat Hedorah Terrorizes San Francisco level |
| Jet Jaguar | Defeat Orga Thrashes Sydney level |
| Manda | Defeat Atlantis Rises From The Deep level |
| Mecha King Ghidorah | Defeat Mecha King Ghidorah Ravages Bangkok level |
| Mechagodzilla | Defeat Cairo Is...Lost In Space level |
| Megaguirus | Defeat Biollante Attacks Paris level |
| Moguera | Defeat Mecha King Ghidorah Ravages Bangkok level |
| Orga | Defeat Orga Thrashes Sydney level |
| SpaceGodzilla | Defeat Monster Island, The Final Battle level |
| The Sphinx | Defeat Cairo Is...Lost In Space level |
| Titanosaurus | Defeat Ebirah Swamps Tokyo level |
