Mega Man II

Mega Man II, known as Rockman World 2 (ロックマンワールド2) in Japan, is the second Mega Man game for Game Boy.

Overview
Like its predecessor, Mega Man: Dr. Wily's Revenge, Mega Man II reuses content from the NES games, both graphics and actual level construction. The first four available robot masters are from Mega Man 2, while the last four are taken from Mega Man 3. The game also introduces many of Mega Man 3's features to the Game Boy series. Mega Man is able to slide. Rush also appears for the first time in the Game Boy series, allowing the use of the Rush Coil, Rush Marine, and Rush Jet.

Story
Doctor Wily learns of an experimental time machine known as the Time Skimmer at the Chronos Institute. He proceeds to steal it, and uses it to travel approximately 37.426 years in the future. While in the future, he experiments with the technology of the age and reprograms the future version of Mega Man, taking him back to his own time and renaming him Quint. Using the Time Skimmer and Quint, Wily once again revives a new set of Robot Masters, four of which guard his underground fortress. Dr. Light sends Mega Man at once to take them down and penetrate Wily's lair, but once inside, Mega Man finds another four Robot Masters awaiting him via teleporters. Mega Man manages to defeat all eight of his adversaries and engages Quint in combat, defeating him and obtaining his weapon, a pogostick-like device called the Sakugarne. With it, he makes his way to Wily's space fortress and defeats him yet again.

Final Boss
After you have defeated all of the bosses, you must fight against Dr. Wily, who is using Wily Machine World No. 2.

Trivia

 * In Wily's stage, there are melting clocks in the background like in Salvadore Dali's painting The Persistence of Memory.
 * The sound effect when the player picks up an extra life is very reminiscent of the coin pick-up sound from the Super Mario Bros. series.