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.
YMMV: Kingdom Hearts: Birth by Sleep
Americans Love Braig: He's much more popular in the US than in Japan. Maybe his Californian accent in the English dub has something to do with it.
Best Level Ever: While the 358/2 days version of Neverland had a better theme, the Birth by Sleep version of Neverland is often considered to be the best one - in part because you actually get to go to Neverland instead of the outskirts.
Best Boss Ever: Ventus gets to make Captain Hook's day a living hell. Several other boss fights stand out - Terra has Braig and is the only one to actually fight Master Xehanort, Aqua has Maleficent Dragon, Captain Gantu, and Braig.
Broken Base: There was a MASSIVE Internet Backdraft after it was revealed that Vanitas looked just like Sora, as at this point many have grown sick of Sora clones or counterparts.
Both Cloud and Leon's backstories got axed so that Organization XIII's original selves could get more screen time. You can imagine how well fans of the characters took that. This especially holds true in regards to Lea and Isa, who unlike the rest were never said or even hinted as coming from Radiant Garden, so Cloud and Leon could have very easily taken their place and the scene would still work.
There's also slight debate on the continuity of the novelization of the game concerning Vanitas's backstory that paints him in a much more Woobie Destroyerof Worlds light. Some people think that it doesn't make sense when compared to the actual character in the game and enter it under Fan Discontinuity, others accept it and think it fleshes the character out more. Then there's fangirls who take it as an excuse for Draco in Leather Pants towards Vanitas.
Even Better Prequel: Many regard this game as one of the better in the series, if not the best, mostly due to its battle system (which is regarded as the most polished, refined, and just plain fun one yet), the interesting story and refreshing three-POV narrative.
Evil Is Sexy: Vanitas. You don't realize this until the end of Ven's story, when he unmasks himself and reveals that he looks just like Sora... except with a more muscular build, black hair, and gold eyes.
"Funny Aneurysm" Moment: Pretty much everything Zack says, from proclaiming he's going to be a hero someday to asking Aqua out after he becomes a hero. We do not know what happens to him later, but we have not seen him in games taking place later, and we know what happened to him in his series. The final end credits sequence shows he looks startled and then disappears leaving nothing but a single black feather. Three guesses who took him, and the first two don't count.
The Command Board and Mirage Arena are pretty much game-breaking mechanics. You can head to the Mirage Arena right after you complete the character's first world, start playing Command Board there to level up commands quickly without fighting, and use the medals you win to buy Synthesis items for fusing. You can even play the Command Board at your first Save Points, and if you know what to fuse and have the patience to keep playing the board you can get pretty much every high-level command in the game almost when you begin your journey. For example, buy an Abounding Crystal from the Arena and use it in a fusion of Blizzard and Aero. You'll get a Command with the EXP Walker ability, and for the rest of the game you'll now get Exp just by walking around.
As another example, level up three Fires and two Aeros, fuse two of the Fires into Fira, fuse that with the third Fire to get Firaga, fuse the Aeros into Aerora, and then fuse Firaga and Aerora into Fission Firaga. Now repeat the process with the Fires to get a second Firaga (or if you have the cash, just buy one from a Moogle), and fuse that with Slow to get Crawling Fire. Now fuse Crawling Fire with Fission Firaga. Congratulations, you just got Mega Flare before you even got to your second world.
Rhythm Mixer edges on this against bosses, due to its speed a well placed combo can hit nearly a dozen times. The only drawback is how long it takes to activate and you can either eat ice cream or spam Thunder Surge to go around that. Using it against No Heart makes the fight go far faster.
Firewheel. With it equipped to Aqua, you can quite literally cartwheel your enemies to death while taking little damage yourself. Some of the more difficult Mirage Arena challenges can be beaten this way. And you can get it before ever leaving your first world note All you need to do is meld 2 fully leveled Fires together to get Fira, max out it's level and meld it with another fully leveled Fire to get Firaga and max out it's level. Buy a Cartwheel and level it up then meld the two together.! On the other hand, Firewheel lacks the invincibility frames granted by Cartwheel, making it a very bad ability against some bosses (such as Vanitas Remnant).
Magnega makes groups of enemies pushovers. It conveniently gathers all enemies in a circle overhead and does continuous damage, and few enemies are immune. The group of enemies makes it possible to obliterate the entire flock with a group attack like Thundaga, Fission Firaga, finishers, etc, and when the next wave spawns guess what, the Magnega field is still there to pull them in to set up for another blast.
The Mandrake Unversed, small plant-like enemies that shoot projectiles at you from a great distance and tend to spawn in trios, ensuring a constant rain of fire. They'll interrupt your attacks, stun you for other enemies to land hits, and will definitely annoy the hell out of you. They also attack OUTSIDE of combat!
If you get too close they spray you with a mist and mix up your controls. Too bad you have to walk right up to them to cause them to exit their invincible, projectile spam phase.
Tank Topplers are large red enemies that are very easy to damage, but when you hit them enough they turn red, become invincible, then roll around to distract you and eventually explode to damage you. The only way to prevent this is to hit them from behind, or to kill them so quickly they don't have time to turn red.
Magnificent Bastard: Master Xehanort. He makes Terra run off and fight the Unversed, making his darkness stronger so Xehanort can take his body. He keeps Ven fighting Unversed and Vanitas, gets Terra to help him kill Master Eraqus, and then brings all of his plans together in one place. And they all almost worked!
Aqua. There's a reason she's given the title "Master" at the beginning. Due to the timeline, Mickey hasn't quite reached this point, but he's getting there. Heck, Aqua's final battle aside from her REAL final one with Terranort has Mickey fighting alongside her. Memetic Badasses fight together!
Vanitas has been propelled to this title, alongside being crowned as a Memetic Molester.
Memetic Sex Goddess: Aqua has been declared the sexiest character in the series by many. The fact that she's older and breaks the Damsel in Distress patterns set by previous female protagonists probably helped a lot.
Mis-blamed: Yep, a few scenes were changed. Braig's telescopic scope was modified to look less realistic (and he's not shown attaching his guns into a sniper rifle) in the international release. But would you believe that some people are actually thinking that a scene in Dwarf Woodlands was censored? In the Japanese version, the Queen gets mad and grunts at the mirror, while her anger possesses it. In the international releases? She throws a potion (off-screen) at the mirror. The thing is, though, this was less of a censorship and more of a removal of a Narm moment (see below.)
Moral Event Horizon: It's hard to tell when exactly Master Xehanort first crosses it, but one contender might be, chronologically speaking, forcing Ventus to fight Neoshadows in an attempt to awaken his inner darkness, and then after the Neoshadows win, ripping apart his heart to create Vanitas, nearly killing him in the process. He only gets worse from there.
Narm: The scene in the Japanese version where the mirror sucks Terra in. The queen gets mad, grunts, and her anger possesses the mirror. This was changed in the international version where she instead throws a potion on it.
Never Live It Down: Terra helped Maleficent by accident, and now he's considered to have helped every single Disney villain in the game as a gullible loon, but really the only other occasion was Captain Hook, which is a bit less forgivable. He was suspicious of the Evil Queen, was considering not even going with Hades's advice, and didn't know enough about Stitch to know that Jumba was (technically) a villain. He's not that trusting of villains on sight.
In addition to that, Terra follows Xehanort's advance due to recent events causing Terra to doubt Eraqus and his friends. While the Audience knows Xehanort is the Bigger Bad, nobody, not even Eraqus, knows that Xehanort is truly evil. Yet people, even some on this very site, treat him as a completely idiot.
There's a surprising amount of Terra x Cinderella.
Add to that Zack/Aqua, with the former asking out the latter on a date. It doesn't help that Aqua becomes flustered and needs to compose herself afterwards, with Herc commenting that her face is red. Let's hope the name "Zaqua" catches on.
Also, there seemed to be quite a bit of Ventus/Snow White. As well as some minor Ventus/Aurora.
And Zack/Terra — at one point, the camera takes Zack's perspective and stares at Terra's chest for a good few seconds. It's like Terra and Aqua were given the same romance options or something.
Sidetracked by the Gold Saucer: The Command Board is actually quite fun, as it's basically Fortune Street with the serial numbers filed off. Besides being a fun diversion, your commands level up and you can win new abilities, even if you don't win, so it's never a total waste of time. In fact, it's usually better for grinding abilities, and some powerful Commands like Ragnarok can only be attained there, while with luck ones like Firaga can be got there before you enter the first world.
When he's possessed by Hades, Zack flips out and gets what is essentially Omnislash. It deals massive damage and stuns Terra for the entire duration once he's hit, requiring constant dodging. The biggest problem with this attack is that Terra cannot dodge attacks at all because he uses a slide. This means you have to get extremely lucky with you timing to avoid it, as guarding is not going to work.
Whilst the Unknown's entire moveset is basically this, one in particular stands out: Collision Magnet, often called the Rape Rope. Simple idea: he jumps high into the air, latches onto you with his laser beams, drags you up into the air and slashes you. The catch? The attack will almost always take you down to 1HP (kill you outright without Second Chance and Once More), and it actually stuns you briefly once you get hit. This means that it's entirely possible for him to follow it up with another Rape Rope, which you'll have no chance of surviving (although he more commonly uses Tornado or his Combos afterwards). To add to that, it has a fairly wide attack radius, and it homes in on you. So yeah, don't get hit, or else you're pretty much dead. Have fun beating him with Terra.
Quite a few. Among them is the first boss of Ventus's Story. He not only has a knee-jerk spin attack that makes getting close to it a dangerous proposition most of the time but is it even has an attack where it throws off a bunch of fruit that look like fire crackers. There are many more than you would expect. This is not helped by the fact that it's very unlikely that you'll have a Cure spell at this point. You do, however, have D-links, which act as a free heal on activation, and - if you're Terra or Ven - Aqua's D-link specifically, which has Cura right outta the box.
Zack, particularly the second time Terra fights him.
Vanitas can be quite hard the first few times you fight him.
Trinity Armor is quite tricky if you're unprepared, being made up of three parts, each of which has enough HP to be a boss on its own, and it has several attacks that can be a pain to dodge.
Master Eraqus hits ridiculously hard.
Terranort, any battle. 'nuff said. note To explain, he's extremely fast, almost never stops attacking, and hits very hard. Long-range attacks are recommended (as he has some really hard-hitting short-range attacks), but good luck finding an opening to execute them!
That One Level: The Mirage Arena's "Treasure Trove" mission takes place on a two-tiered battle field where the upper level is quite a ways directly above the lower area. The only way up there is to bounce off one of three bumpers and then steer your character on top (probably wrestling with the camera), and since it has no walls, it's easy to find yourself going off the edge as you bash enemies, necessitating another frustrating trip back up if they aren't nice enough to chase off after you. Did we mention that the enemy waves switch their spawning back and forth between the two levels several times throughout the mission?
That One Sidequest: Some people found it easier to unlock the secret movie from Kingdom Hearts II by playing the game on proud mode. Birth By Sleep is much, much worse.
True Art Is Angsty: This is without a doubt the darkest Kingdom Hearts game yet, with Days coming in a close second. The response upon finding out the endings in the Japanese version? That Square Enix and Disney have finally grown up. Never mind that Square-Enix had made darker games in the past; even before they merged into Square-Enix, and that Disney has been plenty dark on many occasions.
Uncanny Valley: Unmasked Vanitas. Now, the "evil Sora" face can mesh with a bodysuit, but not with a Riku-esque battle stance. It just feels so... unnatural.
There has been much fan-gushery about Ansem's youngest apprentice, Ienzo, who evidently lost his parents and is now being raised as another scientist in a house of thirty-somethings. Of course, it doesn't hurt that he will grow up into one of the series' biggest fangirl magnets, either... But considering that he is the one who convinced Ansem to pursue their studies on darkness in people's hearts, helped banish his own adoptive father to the Realm of Nothingness, and then became a member of Organization XIII, Ienzo/Zexion is even more of a Jerkass Woobie than Terra, in that you want to slap him for willful malice rather than from stupid naivete.
The novels tint Vanitas to be a Woobie, Destroyer of Worlds instead of the unrepentant monster he appears to be in the game. In the novels, any anger he feels results in an Unversed being born from him, and no matter how many times he tries to destroy them, every time he does, he feels an unbearable pain as a result. The cycle continues, and it is hinted that his reason why he wanted to reunite with Ventus was more or less salvation for him. Again, this is only in the novel adaptations; in the game, there is never even a remote hint that Vanitas feels any sort of pain when spawning or re-absorbing Unversed (if anything, he seems to enjoy it when he's seen doing it! Then again, maybe he LIKES being hurt.)
Woolseyism: Aqua's famous My Name Is Inigo Montoya moment. In the Japanese version she only says "Return my friend's heart!", but leaving it at that would have created a Lip Lock moment. Instead, the English localization team extended it to match Aqua's lip movement, creating in the process arguably the biggest Badass Boast in the entire franchise.