Yeah, I know "adequate" isn't exactly an attention grabber for a review but I couldn't think of another way to describe this game. However, I will elaborate.
The game's plot revolves around multiple dimension-like worlds in the Disney and Final Fantasy universe. Kind of like a Mickey Mouse version of the show "Sliders". Anyway, you have to travel to all of these worlds looking for your standard bad guys the Heartless. Your main character, Sora, holds the key to defeating the Heartless and setting things right again. I'm not kidding, he actually uses a weapon called a "keyblade". And you thought the gunblade was original. In your travels you'll go to Agrabah (home of Aladdin), Wonderland, Neverland, Olympus, Tarzan's jungle, and others. All the while encountering critters from Disney cartoons and Final Fantasy games.
Being a Final Fantasy fan, the major draw for me in this game was seeing Final Fantasy characters from Final Fantasy 7, 8, and 10. Unfortunately, this is one aspect of the game that disappoints. Cameos are limited. I haven't played through the entire game but it seems that the only characters playing significant roles are Leon (aka Squall from FF8), Cid (from FF7), and a little bit from Yuffie (FF7) and Aerith (Aeris/FF7). Sure old favorites Cloud and Sephiroth make appearances, but they don't play major roles in the game. And in the end, you could easily replace them with normal, original NPCs. Square's number one reason for including them is to pander to the Final Fantasy crowd. Mission accomplished, I bought it.
You'll mostly be encountering Disney characters. Disney NPCs, Disney party members, even Disney summon monsters. For me, all that Disney stuff would make me vomit, but it isn't as childish as you would think. Donald and Goofy provide you with battle support and they're good for a laugh in cutscenes. On the downside, all of the worlds I've seen so far are Disney worlds, nothing from Final Fantasy, or at least anything original - except for the first island you start on, and that reminds me of Besaid from FFX.
The voice acting in the game is short. Most of what you see are dialogue boxes or speech bubbles instead of actual voices. But the voices that are in the game are excellent. Square and Disney actually hired some professional talent for a few of the non-Disney characters. And even the Disney characters are voiced by either the original voice actor from their respective movies, or the actor from the TV series spinoff (in a few cases). The dialogue is a little choppy in some areas, but it's not as ridiculous as some of the translated dialogue in other games.
Play control. Jeez. Controlling your character is relatively easy. Battles are a little tougher because of the battle menu, but they do provide a few shortcut buttons for magic, etc. The absolute worst thing is the platform jumping. Between the camera angles and your nitwit sidekicks, it's difficult to land some jumps. Donald and Goofy are constantly in the way, they follow you around like the characters in Final Fantasy 8 do, unfortunately you can't walk through them. I had to push Goofy off a ledge a few times just to see where I was going. They do add a remedy for the problems - a first person "look around" view. It helps to see around and to line yourself up with a jump, but it doesn't help if you turn the camera around to look for a platform only to see that annoying duck standing in your way. And in battle they were basically useless for me. After playing Devil May Cry, I'm good enough with melee sword combat that I don't need the backup of a giant dog with a shield and a duck who can't hit a monster the size of a building with a fire spell.
The minor problems aside, the game has its strengths. The story and the cutscenes make you feel like you're actually controlling a Disney movie - not necessarily a bad thing. And the freedom of movement in battles was a nice change from turn-based Final Fantasy combat. It's no Final Fantasy X, but Kingdom Hearts ranks as one of the best RPGs I've ever played.
-Great battle system
-Top notch voice acting
-Music is good and it sets the mood in certain areas
-Original and engaging story
-Donald and Goofy get in the way
-Other members of your party aren't very helpful in battle
-Final Fantasy angle not as prominant as many would like
Overall I gave it four stars taking into consideration the flaws. If you're looking for an original RPG, I would recommend this game. But if you're looking for a Final Fantasy clone, this isn't it. Otherwise I think everyone should give this game a shot. Rent it first, and if you like it then buy it.