Kingdom Hearts: Chain of Memories is a satisfying experience, despite its flaws.
It's tough for me to say what's so great about this game, however, given that I can clearly identify its flaws. The first weak point I identified was the story. Upon entering Castle Oblivion, everyone starts forgetting things. This led to many annoying dialogue exchanges (Hey I know you! Wait... no I don't. Who are you?) and I fully expected the kind of amnesia-inspired plot line to which gamers are all too often subjected. The writing isn't that great either. I think "heavy handed" is the best way to describe it, considering the aforementioned dialogue is repeated over and over in different situations. Okay. I get it. Everyone is losing their memories.
Another plot related complaint is that, later in the game, new black-cloaked bad guys are introduced over and over. You meet one, defeat him/her, then another enters, scolds the previous one for sucking, and then you beat him/her. This is all well and good, but it happens so often that you will no longer be intimidated by the Organization members. This is because you know that there's another, stronger member just waiting for you to beat the current strongest one.
These complaints aside, if you give it time (and forgive the writing), you will find an interesting story. It is more than just a "I forgot but I beat the boss so now I remember" story. It raises some interesting points about the nature of memories and really got me thinking about my childhood memories that have mostly faded but will never truly leave me. And despite the amnesia mechanic, new story elements and regained memories are introduced at a good pace, keeping the story interesting, while maintaining its mystery.
My other main criticism is that the levels are very simple. There are three locked doors in every level, and three keys that will unlock them. When you unlock the first, you meet the characters for that level and get the next key. When you unlock the second, the plot unfolds and you get the next key. When you unlock the third, you fight the boss. Unfortunately, the one time I found the game deviating from its formulaic level design (Winnie the Pooh's 100 Acre Wood) I longed for the cookie-cutter levels, cause it was annoying.
Also, while the levels definitely are themed after their particular world, they still all work the same, which makes them feel the same. Luckily, your short interactions with the characters themselves (who look great, by the way) infuse the game with enough Disney feel to tide you over.
And in between meetings with Disney and Square characters, you get to enjoy the game's greatest strength -- it's battle system. I know that a lot of people will be turned off by the real time card battling system, but I've found it to be very deep and satisfying. The battling itself isn't particularly deep, but because it happens in real time, it's fast, fun and still strategic. The deepest part of the system is setting up your deck. Sora gains a huge variety of slights (three card combos) and depending on the cards you use (and sometimes the values of those cards), you can execute a ton of cool attacks. When you set up your deck, you have to add cards keeping in mind which slights you want to use, which cards you want to have when not using slights (since they eliminate a card from your deck for the rest of the battle), the best order of the cards and the value of the cards (higher values defeat lower values, but you can equip fewer of them).
While this game has some definite flaws, it manages to pace itself so that you're always having fun. Even if the story isn't amazing, it comes in small, digestible pieces, and the Disney characters add an unmistakable charm. In between the story bits, you get to tool around with an awesomely deep, fast paced battle system, albeit in slightly repetitive-feeling environments. The battling never gets tiresome, though, because the next plot-advancing encounter is never too far away.
A lot of game reviewers overuse the phrase "more than the sum of its parts". I will repeat this cliche, because Kingdom Hearts: Chain of Memories truly is a game that combines a few solid elements brilliantly to become a great experience, regardless of its faults.
EDIT: I'm dropping the score from 8.3 to 7.7. I mentioned in my review that by pacing itself well, the game manages to balance its gameplay so that it's never boring. Well, it seems that that balance is a bit tenuous. Very near the end of the game, I came to a locked door. To unlock the door and advance, I needed a key card with a value of exactly 8. In order to get key cards, you have to fight enemies. I fought enemies for about an hour and I got key cards with every value EXCEPT 8.
In fighting over and over and over, the combat became very unsatisfying. I didn't need to work on my deck, I didn't get to fight a boss or see any of the story unfold, I just fought battle after battle doing the same thing again and again. I gave up after a while, and I will probably never finish the game.
My original score was correct when I first reviewed this game. It's very good when all of its facets are balanced. But when a stupid locked door robs you of the variety, it really exposes how the game's disparate elements are quite lacking on their own.