Mega Man 4

Mega Man 4 is the 1991 Capcom sequel that introduced a twist that surprised everyone: a second villain. After six games of Dr. Wily, a new antagonist named Dr. Cossack appears, and his eight Robot Masters — Toad Man, Bright Man, Pharaoh Man, Ring Man, Dust Man, Skull Man, Dive Man, and Drill Man — must be defeated before the true enemy is revealed. The late-game shift remains one of the NES era's more memorable story beats.

The game introduced the Mega Buster, a new charged shot that allowed Mega Man to hold the fire button and release a powerful blast. The charged shot added a strategic dimension to combat that felt fresh after three games of rapid fire, and it became a series staple from that point forward. Rush received new forms including the Rush Adaptor, which merges with Mega Man to provide a full-body power suit. The stages themselves are polished and creative — Pharaoh Man's pyramid and Skull Man's fortress are fan favorites.

Mega Man 4 is a confident, polished entry in the series with strong stage design and a satisfying weapon set. The Plot Twist that Dr. Cossack was being coerced, not acting freely, added moral complexity that the series had not attempted before. For players working through the classic Mega Man library in order, Mega Man 4 represents the series at peak technical confidence on the NES hardware.