Dr. Wily's Robot Manufacturing Plant

Throughout the Mega Man series, Dr. Wily have constructed massive fortresses to act as his base of operations. Not only these omnious buildings serve as a safe haven from Mega Man, they are also giant factories built to churn out Wily's mechanical minions. These often serve as the final stages where they were full of deadly traps and dangerous robots.
In the first Mega Man game, Wily's hideout was a robot factory built somewhere in the Pacific. In Powered Up, it was renamed Castle Wily.
Area 1: Outer Walls
The fun start with three hopping mad Big Eyes. After you get past them, you'll have to break through the walls using either the Thunder Beam or Super Arm. After jumping, climbing, shooting and dodging your way through mad machines and sharp spikes, you'll go toe-to-toe with the giant Yellow Devil!
Area 2: Skyway
Carefully jump over the broken bridges while avoiding the Bombombs, Bladers, and Screw Bombers. After fighting past Cut and Elec Man, you'll come face-to-face with... YOURSELF?!
Area 3: Hydro Drainage
These sewers are all clogged up with Killer Bullets, Pengs, Octopus Batteries, and Screw Bombers. Soon after the stage started, you'll find yourself washed all the way to the seven CWU-01Ps.
Final Area: Wily's Inner Sanctum
This is it! The final level of Mega Man! Screw Bombers, Watchers, Bomb Man, Fire Man, Ice Man and Guts Man are all the separate you from your appointment with the mad doctor! Good luck!
Fun fact: In Mega Man Powered Up, the second and third stage swap places. Also in the third stage of that game are the teleporters that take you to the rematch with the Robot Masters.

Credits:
Wily's factory by CAPCOM
Art by me!