Metropolis Zone (Sonic the Hedgehog 2)

Metropolis Zone is the eighth Zone in Sonic the Hedgehog 2. Unlike the previous seven Zones, Metropolis contains three full Acts, considered much larger in size compared to the acts of the previous seven Zones.

Description
Apparently a metropolis in name only at this point, the level sees Sonic and Tails make their way through a bustling industrial plant. Meter-wide screws and bolts tower up into the caves of turquoise steel, crushers eternally press into the ground in triumph, mid-air floating conveyor belts and vast mesh-work dynamos thrash out hundreds of revolutions a minute. Along the walls, steam-pipes coil like brassy pythons and giant cogs slowly grind out immense manufacturing processes above lakes of molten metal.

But perhaps the most dangerous aspect of Metropolis Zone comes in the form of the Badniks, for the doctor's city sports probably the most brutal robots of the entire game. Viridian mantis-bots hurl their razor-sharp scythe arms with a boomeranging action, an attack which proves surprisingly difficult for Sonic to dodge and self-destructing starfish drones that are placed with infuriating precision, such that they invariably manage to knock the hedgehog off the giant screw-lifts used to move up the level. There are also crab-like robots that can stop Sonic in his track by punching him with their giant claw at a fast rate.

Boss
At the end of Metropolis Zone's huge third Act, the Doctor breaks out his Egg Mobile for the final time in Sonic the Hedgehog 2. Although this boss lacks any direct offensive weaponry, it remains nonetheless quite difficult in comparison to earlier fights - due to its heavy defensive countermeasures. The Doctor surrounds his pod with a ring of seven orbiting drones, which prevent Sonic from easily landing a hit. If an opening does present itself and you manage to strike him, one of the pods will deploy, releasing a strange, evanescent duplicate of Robotnik's machine. These copies bounce lazily along the floor and can be destroyed quite easily. A variation of this boss later reappeared in Sonic the Hedgehog 4: Episode I.

Trivia

 * The overall zone is the inspiration of Mad Gear Zone from Sonic the Hedgehog 4: Episode I.
 * This is the only zone in the game to have three acts as opposed to the standard two in the previous zones. This is due to the layout for the scrapped Cyber City being reused for the third act.
 * This is the last zone to take place on the surface as the rest take place in the sky.