* Three Robot Masters [[OneHitKill die in one hit]] (or two on Difficult),
** Metal Man. You fight him again in Wily Stage 5 and if you use the Metal Blade (his own weapon) against him, [[WeaksauceWeakness he dies instantly]]. He's the only Robot Master in the series to have [[HoistByHisOwnPetard such a crippling weakness to his own weapon]].
** Wood Man to Atomic Fire at full charge.
** A well-placed volley by the Air Shooter's tornadoes can kill Crash Man in one shot.
* Bubble Man is supposedly the ButtMonkey of the Robot Masters. His weapons are pathetic, he has several [[WeaksauceWeakness weaksauce weaknesses]], and a crippling design flaw makes him unable to walk. Wily could fix the latter, but refuses to because he thinks it's hilarious.
* Quick Man's glaring flaw, that he takes a while to realize he's running into a wall, does offer a few laughs when he continues to run into a well placed Crash Bomb explosion that depletes the rest of his health after Time Stopper is used up. As seen [[https://i.imgur.com/fdySn6V.gifv in this GIF]]
* The weakness of the Picopico-kun boss in Wily Stage 2 is the next-to-useless Bubble Lead.
** And again with the [[spoiler:Fake]] Wily Alien. It absorbs every attack you have except for, of all weapons, the Bubble Lead.
* Even after you defeat the final boss, Wily still continues to control the hologram, until it makes a comical whistling noise indicating it's about to give up the ghost and then stops working.
** The way he ''leaps'' out of the control panel after the hologram stops working just shows how desperate he is for Mega Man to forgive him.