So whats wrong with Mega Man 5, other than it was by far the easiest title out of the NES series?
Didn't have to aim at all with the charged shot and as soon as you did shoot something, Mega's buster charged to full in time to fire at the next enemy.
Just as the blast was about to go off screen, you could time it/line it up to crash into the enemy, to which you were recharging again..
Rinse, repeat, etc.
But I'm probably just stating the obvious.