Mega Man IV (known in Japan as Rockman World 4, and not to be confused with Mega Man 4) is a side-scrolling action platformer developed and published by Capcom for the Game Boy on December 1993.
It is the fourth portable entry of the original Mega Man series and the sequel to Mega Man III. Like the first three games in the spin-off series, Mega Man IV recycles many elements (including bosses, levels, and enemies) from two consecutive titles in the main franchise (this case being Mega Man 4 and Mega Man 5). The game is the first in the franchise to include a "shop" feature, where Mega Man can collect currency (Power Chips) from fallen enemies and use it on restorative items between levels. The game also introduces the "Auto Charger", a passive device in which Weapon Energy capsules are dispersed into the special weapon with the least amount of Weapon Energy.
Set in the year 20XX, the game takes place sometime after humanoid robot hero Mega Man defeated Dr. Wily and his third group of revived Robot Masters (and also sometime after Mega Man 5). At the annual World Robot Exposition, Dr. Wily has used radio frequencies to control all of the robots (with the exception of one: Mega Man). As Dr. Wily scatters eight of his revived Robot Masters, Mega Man must scrap these old foes and confront Dr. Wily again (who has a myserious new creation in store).