These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
That One Boss: However, about half the time, he will spam his lightning attack repeatedly which will cut through your health like a hot knife through butter, especially when his health is low, so if you aren't lucky and he uses this method, he becomes a lot tougher.
"True Heroes," the theme of the final battle with Dark Hero Jet Black, ensures that the second game ends with one hell of a bang.
Badass Decay: Played for Laughs with Alastor, who acts like Joe's cooler-than-thou rival just before his boss fights, but after his "death" starts whining and complaining that he didn't get enough screentime.
Game Breaker: Once you realize you can use Slow and Zoom to increase their damage, Voomerangs make every boss fight roughly a million times easier. Shocking Pink is also a godsend during normal stages, especially the Hulk Davidson one, because it lets you blow things up without having to jump through hoops to get the bomb where it needs to be.
Shocking Pink also lets you create after-images using Mach Speed like beating on an enemy would. This allows you to break containers in the background, which contain lots of points, health and oh-so-vital VFX bar cans that extend your VFX bar.
Ukemi - basically a mulligan for a hit you take in a fight at the last second, which makes it so much easier to get a highly-coveted Rainbow V rating. However, because it only restores one heart when used, it can't undo the massive damage you might endure later on and keep your rankings flawless, which prevents it from being entirely broken. Plus, the move's hard to pull off, given you have to do it right before Joe hits the ground (using VFX Slow to better time the Zoom-in that activates Ukemi does help, though).
Zooming in turns Joe's punches into the Red Hot One Hundred, a speedy flurry of punches. Slowing that makes each rapid fire punch ridiculously strong, without the downside of them being, well, slow. The slowed RHOH is, without hyperbole, Joe's best move for hurting bosses; it can eliminate recurring miniboss the Joker in seconds. Silvia gets a shoulder hit instead of that, making her sadly less powerful than Joe.
Unless she's fighting bosses that don't take the RHOH well in the second game, as she gets Replay, allowing her to triple the damage of any single attack. Slow, Cool Blue Kick, then Zoom In for just as much damage in a single shot. Dr. Cranken, however, is screwed eight ways to Sunday with Replay, especially in his second form, when he takes even more damage per hit.
Red Hot Kick, full stop. You might be surprised that, for an homage to the Rider Kick, it's not that powerful — not so fast bucko. Use Slow-Mo and perform the Red-Hot Kick, then activate VFX Zoom. It turns Joe's attack from a simple diving kick into a spinning drill kick as he's covered by flames in the shape of a dragon head. The Dragon Kick takes huge chunks off most bosses' HP, even stunning Another Joe and Alastor, and can take off almost a full bar of health from Fire Leonote use Mach Speed to build yourself up to Red Hot mode, get to Fire Leo and hit him with a Dragon Kick to destroy his fire barrier. It also, if you're lucky, can hit enemies twice - including, once again, Fire Leo. Fighting fire with fire, anyone?
Even better, the Dragon Kick is a fire-based attack itself, allowing Joe to completely bypass the puzzle portion of, once again, Fire Leo's fight—it pierces through his flame aura. It's knocked out until he dives into the lava below to regain his aura—during which time you can beat his ass like hell.
It does wonders on Frost Tiger, too. Not only does it knock out his chilling flame aura, it strips him of his icy sabertooth fangs and claws, and now he's left shivering and vulnerable instead of spamming boomerangs, icicles, and slashing you to ribbons.
In VJ2, try out Silvia's equivalent of the Red Hot Kick, the Cool Blue Kick, coupled with a Replay attack. This combo rapes Dr. Cranken to pieces.
Zoomed in and Slowed down, the final hit of Dante's normal combo in the first game can one-shotFire Leo.
Goddamned Boss: In the Boss Rush rematch, Charles has 4 times as much health as the first battle. Dealing damage to him, however, is tedious and drawn-out, especially since you start the rematch with a level 1 VFX gauge.
Another Joe is a veryegregious example. He runs away from you and spams unblockable clones at you. Even if you catch him, you can only land a few punches before he runs away. However, if you attack him before he manages to perform his clone attacks, he'll won't be able to do it. The only problem is that Another Joe has quite a bit of health, and you can only attack him five times before he runs away, making Another Joe a very long and tedious boss to defeat.
Try KING BLUE on Ultra-V mode. His health bar is violet when you begin the fight—about ten bars of health. We're talking about the most tedious boss fight in the game with some of the nastiest attacks in town turning into a Mighty Glacier. Whip those Voomerangs out pronto! They'll shave off a few bars!
That One Attack: Several, with anything Fire Leo throws at you (potential One Hit Kills, especially on higher difficulties) and King Blue's thunderbolts (unblockable even while using VFX Slow, do a good deal of damage to boot) taking the cake.
That One Boss: DAMN YOU FIRE LEO! It's made worse by the Boss Rush beforehand. You have to fight four of the previous bosses back-to-back, and you can't save in-between.
Just regular Fire Leo? Try Fire Leo on Ultra-V mode when he uses his spinning attack. With no skull markers to tell you whether he's going to attack high or low, you have to go by audio cues with only subtle differences between them.
Though oddly enough, Leo's frost-themed Expy in the second game is much easier to beat.
Or so you might think. To an inexperienced player, Frost Tiger is just as bad as Fire Leo, just as ruthless, also goes berserk at low health, and the source of many a broken controller. Try facing him on Ultra-V mode or without any clue how to knock out his aura. He gets dialed up to violet health, an absurdly stacked number of colorful health bars that has to go all the way down through the color spectrum to red before finally running out- with Frost Tiger dishing out his critical attacks not even halfway after you've whittled down his enormous wall of health. And he can swiftly kill you in one blow, given the right circumstances. Oh. No. Plus, the icy breath attacks leave you trapped in a block of ice and helpless unless you button mash like crazy. To add to that, don't let Frost Tiger stay on the upper level of the battleground—he'll freeze the platforms above and leave a nice big pillar of ice blocking the path below each time he gets a chance, thus cutting of your escape route, forcing you to either smash the ice, which is painfully durable, trick him into demolishing the ice, or keep whaling on him so he doesn't get a chance to freeze anything- because he'll also freeze the item boxes that contain precious cheeseburgers!!
Also Gran Bruce, to some extent: his (hard-to-dodge) bite attack lasts forever until you break free, which can potentially kill you, even at full health. Mashing buttons or the D-pad will do you no good; only the left analog stick, in a game where the D-pad is encouraged, will let you escape (PS2 version).
It's the left-analog on GC as well, but the stick is actually the primary movement control on that system.
In any case, Gran Bruce is a nightmare if you don't have Voomerangs/can't get the "bomb in mouth" ploy just right.
Ironically, when you fight him a second time, he's actually the easiest of the boss rematches.
Davidson. That frakkin' axe.
He's infinitely worse the second time around, even if you do know what you're doing.
Don't attack; let him come to you and dodge his low swipe three times in a row. He'll then charge like a bull at you. Get out of the way and he'll careen into the wall, dizzying him and giving you a window of opportunity to attack before he pulls out his axe again. If you don't break his axe, you can get him stuck in that loop for the whole fight.
Charles the 3rd the second time you fight him is an absolute nightmare, and it doesn't help that he's significantly stronger and faster than before.
Underworld Emperor Alastor. He has more health than Alastor is his regular form, you can't recover from the first battle against him, and his ROUND TRIP! attack is faster and seemingly more devastating than before. And when his health is halfway gone, he tends to abruptly spam his VORTEX! attack. The only upside to this fight is that you have the opportunity to get cheeseburgers by breaking one of the floating blocks of stone.
Dark Kaiser: An outrageously huge mecha that takes place in the solar system. spams missiles over and over, plays pinball with Jupiter, fires bouncing projectiles from Jupiter's red spot, and makes flaming dragons erupt from the Sun and hurtle through space. You have to kick up Joe's flaming battle aura by punching out the Earth to render yourself invincible to that dragon attack, which can only be done if the boss doesn't hijack Jupiter, causing the Earth to move out of range. It is highly damaging if it hits, and it isn't obvious that you would need to activate Joe's aura, let alone in such a crazy manner. Even then, if you've avoided the dragons and the Jupiter shenanigans, the boss will use Saturn's rings to restrain you if you don't get out of the way, and then bombard you with a targeted missile strike. The only time Dark Kaiser is vulnerable is when it briefly opens up its chest cavity to reveal an energy core and channel an attack. You have to be right next to the mecha to attack it and use Slow and Zoom at once to jump up and do a cartwheel kick and delay the core from receding back into Kaiser, chipping off its health. Sure, you get to be a mecha in this battle, too, so the playing field is fairly even, but Sylvia's mecha isn't so helpful. Hers can't produce an aura against the dragons, or use Mach Speed to flee fast-moving attacks from Dark Kaiser. Replay is quite lovely at doing damage during Kaiser's vulnerable phase, however.
Dark Hero Jet Black is a full-out nightmare. It's already bad enough facing him for the first time when you don't know the key to beating him, but you also have to start the fight de-powered and rely either on Joe's two fists or, more likely, Silvia's boxing glove because of the added range it has. This while Jet has crescent-shaped boomerangs whirling around him—which are damn near impossible to avoid with "Slow" disabled. If you get hit, you take double damage because you're stuck in plain ol' human form... which hurts your ranking each time you get injured... And he spawns another boomerang each time you land a hit.Four times. What happens if you take too long to hurt him or run away? He spams a super-damaging energy blast almost guaranteed to hit you. Guess what else? As soon as you wear him down and get your powers back, you launch right into the final battle with no chance to recover your HP.
Said battle involves Jet spawning an aura a la Fire Leo/Frost Tiger that lowers the damage your hits do. You have to counter it with the respective aura of either Joe or Silvia, forcing you to switch out from Joe to Silvia when you don't want to if he materializes the electric aura instead of a fire one. Why's that? Joe can deliver a rape-tastic series of uppercuts to Jet as he tries to run away while Slow and Zoom are both active. And even if you manage to knock out his aura and get a shot a doing some real damage to him, Jet summons his own dark aura to fortify himself against damage, which can't be countered, and then screws around with his very own Slow and Mach Speed effects. In Slow, it's nerve-wracking trying to avoid his sword slashes—some of which aren't able to dodged via V-Take and get you stuck in a Cycle of Hurting if he lands the attacks. Worse, the gravity is effed up, forcing you to use Mach Speed to descend to the floor-just as Jet catches you to take a slash at your health. His rising sword slash is particular savage and requires a well-timed Slow to dodge. Mach Speed is pure horror, considering it allows him to become a Lightning Bruiser with his katana. Then there's his Beam Spam attacks all over place, including the aforementioned huge one. And finally, Jet mimics the Red Hot/Cool Blue Kick by sending a multidirectional version of their shockwaves from his katana, which fans out into two elemental dragons and can't be dodged, only outran. Good luck, motherfuckers. You'll need it.
Apparently, of ALL the videos on the internet of people facing Jet, only ONE person has managed to do it on Ultra-V, and it took him THREE TRIES thanks to recording errors. In all its amazing goddamn glory.
In all fairness, though, as a whole, the two-part battle against Dark Kaiser and Dark Hero Jet Black isn't quite as bad as the fight against King Blue and Young Captain Blue. At the very least, the former has the bosses split up by Acts (thus allowing you to save), whereas the latter is one long gauntlet, including the actual second act of that chapter, which is swarming with Elite Mooks and stage hazards out of the wazoo.
Villain Decay: In the anime, it was obvious that Hulk Davidson, Gran Bruce, and Charles the 3rd would go down easy... But you'd never expect Fire friggin' Leo to go down in his first appearance, humiliatingly, even!
Fandom Nod: This makes perfect sense when you consider that most of the fans were aware of Fire Leo's status of being That One Boss and were very happy to see him get trounced so quickly after suffering to beat him in the game.