A good game from start, carefully balanced and with a very interesting story. A "must-have" for all PS2 fans.
The story in FES picks up right after the events of P3. You are now in the shoes of Aegis as you try to unravel a rather interesting but old style puzzle. The days repeats itself endlessly but with a rather interesting twist. You can are all aware of that but can't reach the outside world. Very interesting indeed as you exploit an old puzzle from old movies, but that's not all there is to it.
The dungeon and persona system are not far off from P3 but that's a good and realistic change. There can't be 2 identical persons, right? As expected from a harder version of the game there are some limitations which make the game harder for you, but also more interesting and challenging. Since you are no way as strong as the main lead in P3 you cannot fuse all Personas but then again there is no need for that as those you can fuse are all you need to beat the game and P3 already had a quite large number of personas and couldn't even get to use most of them. Also this is like an extension for P3 you don't have access to all the feature P3 had suck as Social links, weapon fusion, compendium and stats, but there is no need for them as this makes the game a lot more interesting, allowing you to be careful at what you fuse, what you fuse and when you fuse them.
Unlike P3 here the difficulty rating for pretty much everything is increased, not that much, but enough to make it more challenging and boss fights... Well these are way better than those in P3 since now tactics are almost always necessary. Unlike P3 teamwork really matter here since you can't blindly charge in and expect to win, at least at the beginning you can but as the story progresses you will find yourself in a position where you need to train some of your comrades just to get past a certain boss, which is way better than always getting the same old company for each fight since it's well balanced. Even though you will die a couple of times when times get hard you will get a greater picture of who should fight who and who is not fit for a certain fight.
The progression of the story is a little far fetched as it only progresses once a you clear a certain level and then get to the last level, but that itself is excusable after you reach your conclusion to why you are there. The story however does not miss any twists but they come in a little too late when you probably think that the game is boring. True, but that's when the true story of FES barely starts and keep you on the edge until the final moment.
All I can say is that FES is definitely worth playing only if you played P3 before. If not you should cause you will miss all the important stuff.