Noise Crush Quick Kills

Shade Man's weapon bounces off walls, creating a unique opportunity to have a shot bounce around a robot master's room.

In theory, this can be used to strike a boss the moment its life meter appears, reducing it from the first HP it gained to 0, killing it.

In practice, even with the use of options to get Noise Crush early, there are only 2 viable places to use this trick - Spring Man and Turbo Man.

Execution

Mega Man must fire the noise crush as he moves into the gate, making the noise crush spawn on the other side of the gate and bounce around the room.

As a slow method, you can tap right and Y at the same time to have Mega Man inch forwards. This is slow, but faster than the boss fight. Faster methods certainly exist.