Mega Man and Bass/YMMV


 * That One Attack: King Jet will reveal its power crystal, begin charging up, then will blast the entire screen. Perfect King has this as well. Destroy the crystal before it finishes charging.
 * That One Boss: Burnerman. He has a charging attack that's tough to dodge and deals a ton of damage, his Wave Burner can block your shots and pin you in a spike-filled corner, and he sets beartraps that grab and hold you, leaving you wide open to attack. Also, there's the issue with his weakness; while most bosses in the series will let you get away with just spamming their weakness until they're dead, Burnerman will not. Fighting him with the Ice Wall turns him into a bit of a Puzzle Boss that requires you to push the wall into him, forcing him into the spikes on either end of the room, a task that's easier said than done.
 * The other major candidate is Dynamo Man. Unlike Burner Man he is very vulnerable during most of the fight. The problem is he spends most of the fight in Beam Spam mode. He also forces you into a Sadistic Choice of forcing him to fire hard-to-dodge projectiles, or guessing where his Lightning Bolt will strike with no warning (there is a pattern to his Lightning Bolt, but it's incredibly hard to pick up on, requires split-second precision, and you can mess it up by walking just a few pixels too far). Finally, he will jump into a recharging station partway through the fight and will completely heal himself if you don't destroy it quickly. The Copy Vision will trick most of his attacks and let you focus on dodging the rest, though.
 * Magic Man loves counter attacks, and all of his attacks require a different response. The Tengu Blade must be properly timed so you hit him and not his projectiles. Sliding through him with the blade deals extra damage (and he drops his cards!) but you have to start it RIGHT in front of him or you'll take Collision Damage.
 * There's also the King Jet. You have to fight it on an Auto Scrolling Level, having to constantly jump from one small platfrom to the next. The Jet itself does everything in its power to make you fall, including sending out flashbangs, a Rocket Punch that destroys any platfrom it collides with (often the one you just started to jump to...), and finally the above-mentioned Wave Motion Gun, which can at least be countered by destroying its power crystal before it finishes charging. The Jet has no apparent weakness, and no lifebar so you can't even tell if you're doing much damage or not. At least the game was kind enough to make an infintely-spawning 1-Up appear shortly beforehand so you can retry the battle as many times as your sanity allows.
 * That One Level: The second level of King's fortress could have been broken up into three levels easily. In fact each section ends with a boss: King Tank, King Jet and King himself. The King fight is also three phases long, just to add to your misery.