Mega Man IV is the fourth in a series of handheld ports of the successful NES games. The Gameboy versions come into their own with this game, which goes beyond a mere port, introducing features that would later be included in main series titles.
Gameplay is mostly the same as other entries in the franchise. Players attempt to destroy 8 robot masters, then defeat Dr. Wily himself. As each boss is destroyed, its special attack is gained for use against future enemies.
This version includes four bosses from the NES Mega Man 4 and four from Mega Man 5, though the stage designs are new, not copies of the NES version. It continues the tradition in the Gameboy series of giving the player only 4 stages to choose from at the start, followed by an intermediate stage, then the next 4, and finally Dr. Wily's fortress stages.
In addition to the 2 Rush adaptors gained along with weapons when defeating specific bosses, a special weapon (the bird Beat) can be obtained by finding special plates in the first 4 stages. Similar plates in the second set of stages must be found to unlock the final section of the game. Like the previous game, a new special boss rival, Ballade, is faced during the intermediate and final stages.
The most innovative feature is a shop and currency system for buying items with the 'p-chips' found in stages. New purchasable items included mini energy tanks, weapon energy tanks, and the energy balancer. Finally, some stages had secret areas that could be accessed using one of the special weapons. Many of these features were included in later Mega Man games, beginning with the 7th.