Mega Man: Dr. Wily's Revenge

Mega Man: Dr. Wily's Revenge, known as Rockman World (ロックマンワールド) in Japan, is the first Mega Man game for the Game Boy.

Overview
The game recycles content from the original Mega Man for NES and its sequel, Mega Man 2. At the start of the game, only four robot master levels are available to choose, all of which are from Mega Man. The second four robot masters, all of which are from Mega Man 2, are fought as bosses in the Wily Stages of the game. This would become a staple of the Game Boy games until Mega Man V, the only Mega Man for Game Boy not to recycle large amounts of content from the NES games.

Story
Dr. Wily once again sets his sights on world domination. This time, he revives several of his Robot Masters, giving them another chance to do battle with Mega Man. Four Robot Masters rampage across the globe, so Dr. Light sends Mega Man out to stop them. Once they are taken down, Mega Man heads to Wily's fortress only to discover that four more Robot Masters await him there. To make matters worse, Dr. Wily has constructed a new powerful robot, a Mega Man Killer known as Enker. Enker has the ability to absorb Mega Man's plasma shots with his lance and return a powerful blast of energy at him with his Mirror Buster; however, Enker is defeated, and Mega Man chases Wily to his space fortress above the Earth, using Enker's own Mirror Buster to defeat him.

First Four Robot Masters
Unlike its NES counterpart, only four Robot Masters are available to choose from in the start of the game. These four are taken from the original Mega Man.

Second Four Robot Masters (Wily Teleport System)
After the first four Robot Masters are defeated, four others must be fought in Wily's Fortress. These Robot Masters are taken from Mega Man 2.

Final Boss
After Enker is defeated, you must fight the Wily Machine World No. 1 in Wily Station.

Trivia

 * In a first moment, the game was called Megaman World, also, the Rom had sprites with theMMW1mys-world.gif word "World" in the title screen, for uknown reasons the title screen was change to only for Mega Man.