A Mirage of Mind: Gaia is the final stage of Metal Black.
The Black Fly finally reaches the star Nemesis as close as it can get to it. The player encounter strange rock formations and what appear to be remnants of a strange mechanical object scrapped together before encountering the heart of the alien forces where the plot unfolds.
The boss of this stage is Omega Zone.
- Although it is based on an Elephant Jellyfish, the whale shaped look of Omega Zone is a possible reference to Great Thing.
- If the player dies in this stage and decides not to continue, the bad ending will be unlocked, revealing a massive launch of Black Fly's leaving the Earth, preparing to attack the enemy.
- However, if Omega Zone dies, the good ending will be unlocked, a text can be seen as: Was its phantasm the last attacking or its last moments and was this for real or i was dreaming nobody knows yet.... And finaly, the Earth revives and a sunrise is seen, marking the end of the game.
- During the fight with Omega Zone, the song played is a medley of most of the previous songs of this game. The song and the Omega Zone's difficulty changes as damage increases. The songs included on the medley are strictely on the following sequence: "Yueez", "Visitor", "Dio Panic!", "Born to Be Free", "Dual Moon", "Gate of Guardian", "Area 26-10" and "Time".
- Along with the music, the stage background changes as Omega Zone's damage increases. The backgrounds represent different periods of the history of the Universe and Earth and its possible future as well.
- Background 1: Black space - The absolute nothingness in the Universe, prior to the Big Bang, 13.798 billion years ago.
- Background 2: Negative-colored Monochromed Galaxies - The Big Bang, and the creation of the Universe as we know it.
- Background 3: Dinosaur fossils - The Cretaceous-Tertiary Mass Extinction (K/T Extinction) 65 Million years ago, which wiped out 75% of all life on Earth, including the Dinosaurs, clearing the path to the evolution of mammals and opening the doors to the primitive human beings.
- Background 4: Primitive Man (Homo Erectus) - Age of Mankind, with the extinction of the Dinosaurs, the hominids like the Homo Erectus will evolve to the modern-day Homo Sapiens, becoming the new dominant species on Earth.
- Background 5: Primitive Man with Train Wagons on the background - Mankind's Power of Invention and the Creation of Machines. Millions of years of evolution gave humans the hability to create tools and machines, surpassing the limits of the human body imposed by nature, leading to the technological progress of the human race.
- Background 6: Soldiers, Tanks and Jets - Weaponization and Militarization of Mankind. The power of invention brings the creation of the weapons, although weapons were made for hunting and survival, they became a negative side effect of the technological progress of humanity with the creation of warfare and weapons of mass destruction, becoming the cause of most conflicts and wars throughout human history.
- Background 7: Ruins and waste - Collapse of Civilization due to a Global War, leaving Earth and human beings on ruins. It could also be a Garbage Dump, representing the pollution of Earth caused by human beings.
- Background 8: Ruins and a Cat with strage eyes - Mass Insanity, with the collapse of the civilization and society, mankind will face a state of mental breakdown, leading to massive hysteria and paranoia.
- Background 9: All previous 8 backgrounds and Earth breaking in two - The culmination of all the negative actions of mankind leading to the total destruction of Planet Earth and the end of life on the planet as we know it. It could also represent the end of the cycle of creation and destruction of life, the world and the universe.