A year after the destruction of Gamma and Dr. Wily's defeat at the hands of Mega Man, the world is still at peace.
One day a letter arrives for Dr. Light from a mysterious Russian scientist named Dr. Mikhail Cossack. Dr. Cossack plans to eliminate Mega Man to prove that he is the greatest robot designer of all time. It's up to Mega Man to save the day once again.
Mega Man 4 provides action-based game play like the earlier games in the series. Mega Man now has the ability to charge up energy inside his Mega Buster, allowing him to fire larger and more damaging blasts.