Board Thread:Fun and Games/@comment-36596195-20180815183300/@comment-36596195-20181105015532

Metal Man can be easily beaten if you know the trick to keep him jumping.

Both Metal Man and Bomb Man will jump away from you if you attempt to go near them. Once you are aware of this you can easily lock them in a loop of them jumping to the other side of the screen while you shoot at them. While Bomb Man won't attack you, Metal Man will through one, singular Metal Blade while he's in the air which can be easily dodged.

I usually pick both of these bosses first for this very reason.