Good overall, but a few glaring flaws prevent it from being great.
Dissidia Final Fantasy is Square Enix's own mash-up fighter, with the most recognizable villain and hero from each Final Fantasy (1-10). It's flashy, it's fun, and it's got more unlockables than people in China. Okay. Not that many. But completionists will have to devote a significant amount of time to it. In fact, the game keeps track of everything for you so you know how far along you are. There are achievements, characters, recipes, materials, accessories, weapons, music, icons, friend cards, and moves to unlock. And I've probably missed a few. Bottom line is, this game has a staggering amount of content for Final Fantasy fanatics. But the most important question is: is it fun enough to play and try to get everything?
Yes, and no. The fighting system itself is interesting, but is a little broken. It's dominated by two sets of numbers: Brave and HP. Brave attacks steal brave points from your enemy, and HP attacks deal damage equivalent to your Brave. Which is fine. But then, there's the break system. Break happens when your deplete your enemy's brave points (or vice versa), and the game awards you with a ridiculous amount of extra brave. Thousands. It makes it extremely hard to make a comeback once your brave is broken. I can understand rewarding a brave break, but sometimes, your brave gets boosted 5000-6000 points. Cautiously, it's possible to slowly chip away at it, but it's tough to regain a decent footing. Otherwise, however, the system works well, and brings a completely new fighting system into the genre. There's also a few issues with the camera which happens near corners and ceilings which generally isn't an issue, but it makes dodging attacks a little hard when you're trying to predict your opponents move while staring at a wall.
So far, so good, right? Well, we now go to story mode. I won't spoil any of it, but every story for each character runs in parallel. Meaning that you're basically going to see the story multiple times with different characters (for the first part). Okay. I can understand a fighting game with a lackluster story, but the same story for every character? Not a lot of fun. Especially when the setup of the story mode is basically a board game of sorts. See, you start on this grid with different pieces on it (enemies, items, summons, you, etc), and you move around fighting and getting items. It's got a reward system tied in and a sprinkle of strategy, but it's not much fun. It's almost reminiscent of nightmare of a bored-game (har har) in DMC4. My last complaint is with the English voiceovers. They are terrible. The end.
Overall, it's a solid package. It's got everything a Final Fantasy fanatic could ask for. But its flaws are rather glaring, and in some cases, may kill the fun.