Screenshots of Metropolis Zone from Sonic 2
The Metropolis Zone is a massive high-tech complex controlled by Dr. Eggman.
History[]
Sonic the Hedgehog 2[]
Metropolis Zone is the eighth stage in Sonic the Hedgehog 2. Although Metropolis is supposedly the capital of Westside Island, it doesn't look much like a city at all in the game. The entire area is comprised of industrial machinery, with large rotating gears, smashing pistons and pools of what could be either lava or, more likely, molten steel. Metropolis serves as Dr. Eggman's headquarters in Sonic 2 and from here he controls the entire island, commanding his Badnik hordes to search for the Chaos Emeralds and construct his Death Egg satellite.
Sonic Chronicles[]
Metropolis lies in ruins
In Sonic Chronicles: The Dark Brotherhood, Dr. Eggman appears to be operating out of Metropolis once again. While it hardly resembled a city in Sonic 2, it has since been re-structured into an actual urban/industrial landscape. It is hardly a place where people would want to live, of course. The entire city chokes under clouds of smog and streams of radioactive waste run through the waterways. Broken machines and robots are scattered throughout the streets and Eggman's face is plastered everywhere.
At the start of the game, Dr. Eggman's latest world domination plot is thwarted by Sonic and his friends. The doctor is presumed dead after his latest airship crashes into Metropolis, leaving most of the city a smoking ruin. However, shortly after this event, the Nocturnus Clan secretly move into the city and establish a base of operations there, salvaging several Badniks to help defend their position. Eggman, of course, survived his latest defeat and actually aids Sonic and his friends later in the game, helping the heroes gain access to the Metropolis Underground in order to flush out the Nocturnus Marauders. The Marauders cleared out, but had set the skyborne Angel Island on a crash course with Metropolis, devastating the city even further.
Sonic and friends eventually follow the Marauders to their home base in the Twilight Cage, leaving Dr. Eggman behind in Metropolis to guide the team's re-entry into their own dimension. However, when the heroes return, they find that two years have passed in the hours they have spent in the Twilight Cage. During this time, Dr. Eggman has rebuilt Metropolis and conquered the world without Sonic being around to stop him.
Sonic Chronicles ends on a cliffhanger and it is not yet known if the story will ever continue where it left off.
Sonic the Comic[]
Metropolis Zone as it appears in STC
In Sonic the Comic, Dr. Robotnik conquered Mobius and ruled the planet for years in a totalitarian dictatorship. For the latter half of RBR, the doctor ruled from his capital, the Metropolis Zone (which never resembled the Sonic 2 stage despite being based on it). In the centre of the city stood Citadel Robotnik, the capital building made in Robotnik's own image, where the doctor would monitor the goings-on of his subjects across Mobius and would regularly send out his Badnik Troopers to harass Metropolis' citizens, making random arrests and even sending in Badniks to launch spontaneous attacks against the people just for the fun of it.
In STC's 100th issue, Mobius was blanketed by an electromagnetic pulse that shut down all electrical systems across the planet, crippling Robotnik's empire. With his Badnik armies wiped out and his citadel destroyed by Sonic, Robotnik had finally been deposed and Mobius freed from his tyranny. Since then, the Metropolis Zone has become a decent place to live, mostly. It still endures many of the problems that any major urban centre would.