The Mega Man 4: Free of Charge download comes as an IPS patch file. There are free utilities out there like Floating IPS that can apply the patch file to a clean dump of a NES cartridge.

Capcom released the Mega Man series in 1987 with the NES game Mega Man. The hero, a humanoid robot, was created by Dr. Light to save the world from Dr. Wily and his rebellious robots. The player ...