The game continues the quest of the protagonist Mega Man in the struggle with his long-time nemesis Dr. Wily, who sends out a disruptive radio signal to cause a rampage, citywide destruction from dormant robots.

[5] The plot of the game once again involves the protagonist Mega Man trying to thwart the world domination plans of the infamous Dr. Wily.

[6] Having resisted this reprogramming signal, Mega Man responds by defeating all four of these previous foes in battle and chases Wily to a large tank.

Dr. Light fits Mega Man's companion Rush with a space flight ability, allowing the hero to lead a one-man assault on Wily's new stronghold.

[6][9] Clearing 2 of the Robot stages also gives the player access to abilities from Mega Man's dog Rush, who can transform into a springboard for reaching high platforms or a jet for crossing large distances.

[6][9] On the other hand, the game's latter four Robot stages each house letters that spell ("W-I-L-Y") which would be imperative to collect in entering to the first part of Dr. Wily's fortress.

The artist had fun thinking up new ideas for Ballade's second form, which included the horns on his head turning up, larger bombs, and shades covering his eyes.

[12] Mega Man IV was re-released on April 13, 2001 for the Nintendo Power cartridge service in Japan alongside its four Game Boy counterparts.

[17] On July 18, 2013, it was confirmed that Mega Man IV is planned for release on the 3DS Virtual Console[18] which came out on October 23, 2013 in Japan and on May 15, 2014 in North America.