It's a really good game. Very good sequel, and a satisfying entry in the series. Had alot of problems with it, but despite how negative I may seem to a few things this is still a solid game in which any Kingdom Hearts fan will have alot of fun with.

The gameplay is certainly changed. You still have the basic concept of button mashing introduced in Kingdom Hearts II, but Birth by Sleep added some new mechanics to not only spice things up but also to work around this issue. And there are a ton of them: first off, and the most notable of all, the command system. I totally appreciate the fact that Birth by Sleep tried to change the gameplay, and to eliminate the button mashing issue, but I don't think it worked. There's still a ton of button mashing in Birth by Sleep (even on Critical Mode), and the game doesn't do a good job of motivating you to use the various commands at your disposal. Nor does it do a good job in exposing the benefits of melding commands either, because most abilities you get from melding only get useful during the hardest parts of the game - more on that later.

The game also introduces Command Styles, Shotlock Commands and D-Links...again, Birth by Sleep keeps giving new stuff, which
is great and certainly way better than sequels that just repeat the same thing over and over again, but the problem is most of it is not all that useful besides a few specific situations where it's impossible to go without, except for maybe the Command Styles which not only are very easy to pull but also range form completely pointless (Thunderbolt) to broken as fuck (Rhythm Mixer). It's very fun to pull off these Styles, with lots of flashy combos and cool finishing moves, but after awhile you start wondering what they really add to the experience at all. D-Links are specially pointless, I really can't think of a reason why would anyone use them other than the fact they heal your HP. Shotlock Commands are really broken too, they basically give you a free way to dish out tons of damage while also giving you invincibility while you pull them off. And it's really easy to perform these commands as well - which brings me to my next problem.

The difficulty in this game is not good...at all. I played the game on Critical Mode, the hardest difficulty, and I essentially breezed through most of the game no problem with the ocassional cheap boss or mob group impeding my progress. This game can either be pretty easy, or ball-bustingly impossible thanks to bosses who get alot of invincibility frames and cheap attacks, like Experiment 221, and mob groups that throw insane numbers at you at the same time. It's in these situations where you find use of the Shotlock Commands and the totally broken Command Styles, and these completely transform these otherwise impossible segments into cakewalks. The difficulty is incredibly unbalanced, and this is specially noticeable during the super bosses.

The super bosses are easily my favorite aspect of the Kingdom Hearts games, and Square games in general, but in this game they're terrible! Vanitas' Remnant, Armor of Eraqus, No Heart and Mysterious Figure (I call him motherfucker) are absolutely ridiculous! One thing is challenging like Unknown in the first Kingdom Hearts (he only had one bullshit move) and Lingering Will in Kingdom Hearts II, they were really fucking hard but still pretty fair most of the time and required timing, pacing and an appropriate strategy even though there were many ways to beat them. The super bosses in Birth by Sleep are not difficult, they're cheap and downright unfair to the player. They seem completely impossible to stun and almost every attack downs you to 1HP, and they attack so freaking fast that Second Chance and Once More don't help all that much sometimes even though they're essential. The only way you can ever beat these impossible battles are by either spamming the shit out of your Shotlock Command, dishing out damage while making use of the invincibility frames, or by dogding 98% of the battle while ocasionally performing Thunder Surge for chip damage and its i-fames like a dumbass. You don't feel rewarded when you beat them, mainly because the only way to beat these assholes is to cheese them. No actual skill or strategy is actually used, which is extremely dissapointing because the setting, atmosphere and music during these battles are so good.

Oh well, but even with all that said the gameplay is still good and there's alot of fun to be had. It's fun to kill things with all these flashy moves and long combos, from either your abilites or your Command Styles.

The soundtrack is awesome. While I don't think it's as good or complete as the previous ones, it's certainly better than Chain of Memories and a kickass one on its own. My favorites are "Keyblade Graveyard" and "Ventus", but the remix of "Force del Male" and "Darkness of the Unknown" used for No Heart's boss battle and motherfucker's theme are really fucking awesome as well.

The story is...well..confusing, at best. I honestly gave up on trying to understand what's going on and why, Nomura complicated the shit out of the series' narrative. Stuff happens and I have no idea how or why, characters can just do things because magic...maybe I just forgot some details, but damn was it hard to follow. But despite that, Kingdom Hearts still does a really good job at giving us likeable characters and powerful emotional scenes. What really helps is the excellent presentation, for a PSP game this looks absolutely gorgeous and the HD version looks good for today's standards.

With all that said, it's a really good game and I had a blast with it. It's just not as good as the previous games - yes, even Chain of Memories. I've been planning on completing this game for a long time ever since I got the HD version, and I regret not doing it sooner. Now i'm waiting for 2.8, to play Dream Drop Distance and find out how it changes the gameplay and how it drives the plot further down into the realm of insanity.