I stayed up all night to play Final Fantasy XIII enough to give you guys my first impressions. Read all about what I'm thinking after five straight hours.
Let's just go ahead and get it out of the way up front, shall we? Yes, Final Fantasy XIII is more linear than the other games in the series. A lot of gamers will tell you that it's linear to the point of being bad, but I'm here to tell you as a JRPG purist that the linearity in Final Fantasy XIII is very far from game-breaking. In fact, the linearity brings with it some of the best and most enjoyable content I've gotten out of any of the Final Fantasy games to date.
I myself was a little bit concerned about the linearity going into Final Fantasy XIII, but after playing the game, the linearity works so much to the advantage of it. You see, Final Fantasy XIII also happens to be one of the most story-driven iterations that has ever been released. Final Fantasy XIII has a focus that I have to say I'm loving. Most of the game's first five hours will feed you the story in managable, bite-sized chunks, but via an in-game encyclopedia of sorts, the game is rich with optional content that you can read and take in when you feel so inclined. While I've found it handy to examine the in-game encyclopedia every time there's an addition to it (the game kindly notifies you when there's been an addition via an icon that will appear in the corner), I'm convinced that you could go through the first five hours of the game reading a minimal amount of what's included in it, so long as you pay extra attention to the story as it unfolds via the cut-scenes and CGI. That said, to not read the encyclopedia would be a shame, because the developers put so much time into fleshing out the story, and while a lot of the little details aren't immediately necessary, you'd be missing a lot of the attention to detail to pass it up.
Speaking of CGI and cut-scenes, Final Fantasy XIII is gorgeous. I'm playing it on the PS3, and the visuals are fantastic. The animations in-game are very smooth, and the combat feels very fluid as a result of the well-crafted animation. That brings me to something else that the linearity actually ends up providing to the game: the camera angles and on-screen action has a much more focused presentation as a result of trimming down. There were literally dozens and dozens of moments, just in the first five hours, that my jaw dropped at the visuals.
The combat in Final Fantasy XIII is very unique as well. Take the turn-based formula, throw in a dash of Final Fantasy XII - AI controlled partners - give it a unique type of job system, and then base the character customization options on something loosely based on the Grid Sphere from Final Fantasy X; if you can combine all of those elements together, you have something in the proximity of Final Fantasy XIII. Don't be fooled, though; even though there's a lot of different elements being combined here, Square Enix made all these different elements mesh together in a way that feels very smooth and organic. With a little bit of practice, you'll have the combat system down pat. It's nice to see that Square Enix got two of the most important JRPG aspects down pat this time around: a great story and exciting, compelling combat between plot points.
The character roster so far has done a great job of maintaining diversity, and you really believe in the motives of the characters while simultaneously feeling bad for the characters who just sort of ended up at the wrong place at the wrong time and ended up getting wrapped up in something they really had no part in. There is one character - though I'll save mentioning a name for now - that has a sort of happy-go-lucky personality that does go overboard at times, especially considering the situations that the characters are finding themselves in. But other than this one particular character, I've not ran across any other characters that particularly grinded my nerves. Just be warned that there is at least one character in the game that will probably make you want to take a cheese grater to your face.
There's not one thing I could pick out that makes Final Fantasy XIII such a standout title; it's really a combination of extreme focus and generally well-designed gameplay. I'm sure there's more I could go on about just from the first five hours, but it would be a waste for me and a waste for you. I'd be wasting time I could be spending playing it, and I'd be ruining for you the excitement of being able to go in not quite sure what to expect. But rest assured that, if you're a Final Fantasy fan, this game doesn't disappoint.
EDIT: I did forget to mention the fact that Final Fantasy XIII is very much Westernized from previous entries in the series. The game will restore everyone's HP after every fight, so it won't take you long to have a ridiculous stockpile of potions that are only worth anything in combat. But that shouldn't imply that the game is a cakewalk, because I've already encountered a few bosses that will tear you up repeatedly until you master the intricicies of the combat system. The linearity and Westernization might be enough to turn some people away, but if you're playing for a great story and fun combat, you'll easily overlook the Westernization and linearity.