"Mega Man 4" was the first game in the franchise that let players charge up shots. Capcom called this ability as the Mega Buster; an enhanced version of Mega Man's blaster that was first introduced to the gaming world some 25 years ago.

Before the Mega Buster was created, Mega Man just fired strings of pellets at enemies while running and hopping awkwardly around the screen and just uses a simple attack with low damage firing laser. Because of how the games limited Mega Man's maneuverability and timed the windows for firing accurately on targets, mastering each level required adapting fully to the logic that makes the game impossible to accomplish.

However, because of Mega Man's Mega Busterplayers can charge up their basic attack and this helped the game to be insanely popular since 1991. The Mega Buster has two different fire charge levels. The first charge produces a blast with a bigger radius that can cut through anything it hits, while the second releases a shot with a larger radius that damages three times as the normal attack.

Hayato Kaji is the person behind the legendary idea to let "Mega Man" charge up his shots if a player long pressed the 'B' button of the game console. Mr. Hayato Kaji is a designer from Capcom. He directed and designed almost all Mega Man game series, from "Mega Man 4" up to "Mega Man 10," along with the trilogy of "Mega Man Legends." He is also the character modeler and lead object designer in games such as "Lost Planet: Extreme Condition," "Onimusha 3: Demon Siege" and "Street Fighter II."

The Mega Buster made Mega Man game series easier and quicker to all the fanatic players. It allows Mega Man to conquer through levels more assuredly with an always-ready charged shot reserved. Platforming sections became less tricky considering that upgraded blast can strike multiple enemies at once.

"Mega Man 4" may have some worst boss design in the franchise's history, according to Kotaku; a reliable blog gaming site. But because of Mega Buster, it was also the turning point in terms of premium quality. As a result, "Mega Man 4" deserves to be acknowledged in the whole Mega man series.