Final Fantasy (FF) 7 deserves the praise. Most of the criticism which came years after it was released is unwarranted -- it can be seen as a byproduct of the game's extreme success and popularity as truly one of the best games ever. FF 13, on the other hand, deserves both praise and criticism. It is a heavily experimental game which walks fine lines on most of the major elements in a game: gameplay, storyline, and music.
FF 7 was certainly new but it didn't challenge the major tenets of the series: Nobuo Uematsu continued as the main composer of its music after the excellent FF 6 soundtrack; the gameplay was still largely based on levelling up and turn-based battle strategies; and in the end it was all about becoming as powerful as possible and getting the best weapons through sidequests. There were novel elements, but they were mostly due to the drastic change in technology from the SNES to the PS -- the story was certainly more cinematic and other elements were simply heightened given the better graphics and more memory the PS offered.
FF 13 is quite different. Uematsu is no longer the main composer, and it shows. The Chocobo theme, for example, is now played with lyrics. (?!). Music repeats itself in areas quite often early in the game and therefore fails to give each environment a unique feeling. There are some good songs which draw on experimental jazz and electronica, but I wish there were more classical pieces -- especially for some of the grander environments (I can't say exactly which environments since some would contain spoilers for the plot).
The gameplay is completely oriented around the notion of time. This makes battles extremely fast-paced. That sounds strange so let me explain. In previous FF's, there have been MP costs for magic, as well as other issues to take into consideration such as enemy's susceptibilities to various magics or status effects. These were the central aspects of the strategy. In FF 13, everything comes down to how much time it costs vs. how much time you have. Magic doesn't cost MP, it costs ATB bars. Over time your ATB fills up, and according to how much it has filled up, you can cast this or that spell. Haste is one of the very last spells you learn, which contributes perfectly to my thesis about the centrality of time.
Enemy encounters, in turn, are all about time. It's not simply about figuring out some enemy's weakness. It's about figuring it out and then pounding it with the appropriate magic in order to reach the point of stagger as quickly as possible. At the point of stagger, enemy defense lowers and you are able to, for a brief period, relentlessly assault your foe to cause massive damage. Effectively utilizing stagger can mean the difference between victory and defeat even on regular enemy encounters, and is certainly a central part of taking down the bosses.
Grinding means nothing to approximately 3/4's of this game. This is a huge difference from previous games. Love it or hate it, I at least would have liked some more choice, since the linearity of the game pushes you constantly forward leaving you little freedom to grind or build even if you wanted to.
The story is excellent but yes, as I just mentioned above, it is very linear. In order to make it feel less linear, for the first 3/4's of the game you switch different parties over the course of each chapter. Thus, the gamer is able to gain a sense of different personal conflicts among the members of the party. When areas finally open up later in the game, it's an extreme opposite of the previous chapters.
And so on. The game is intense but it pulls the gamer in such extremes that it is hard to develop a solid love or hatred for the game. And thus I won't be able to give it full points for a full review (which this has basically become!). But the game is definitely a must-buy and most fans will find something in it which they like. I for example really really enjoy the battle system and the story. I honestly feel they are some of the deepest the series has offered. At the same time, I can't get over the linearity of the plot and levels, as well as the horrible music.
Since I've basically given a full review here, I will confine later comments to more discussion of the battle system since it impressed me so much. For the story, you're just going to have to find out for yourself! But I certainly welcome emails if you want to discuss anything, as I think the connections this game makes with religion are some of the most powerful we've seen in an FF.