Without going into spoilers...
In general, it was a well-done game. The story will require spoilers to really talk about, so I'll just say it was a tad bit over-abused, but ended well and was at a forgivable level.
And the final part with the protagonist at the very, very end was really... "wow."
What I really liked was the battle system. The Brave - Default system felt pretty balanced.
-You could not just full Brave and defeat all the enemies you meet,for instance, because:
--The enemy might not die from your attacks
--Getting hit by a status ailment like Paralysis stops your movement and you don't get back the wasted Braves
-You could not just constantly Default 3 times and then full Brave
--Because there is a status ailment, Fear, that drops your stored Brave to 0 and keeps it there
The bosses were balanced too and none too easy, but there is always a method to beat them other than leveling up and pushing with brute force.
However, one complaint I have is the Run Away system in this game. The chance of running away is too low, WAAAAY too low. It is almost always better to fight, because you generally would finish the battle faster than you could run away.
The jobs were fun. You could combine them in different ways for different results, kind of like Etrian Odyssey. There were a couple of jobs that were a bit... useless though.
And now, to talk with spoilers...
The whole world looping thing was interesting, but the writer was the same one that did Steins;Gate, which kind of made me wonder if he just really likes these "separate world" plots too much.
Not that it was bad, but the game itself looped too many times too. At least Chapter 7 was absolutely not needed and had no effect on the story. Heck, 8 didn't either, but there needed to be a bumper between the important Chapter 6 and Last Chapter, so 8 was fine, I guess. But it wasn't the most exciting doing the same thing over and over again. A lot of the sub-characters did the same thing each world too. They gave good experience and JP though. Allowed me to get to Lv99 before I reached the final boss.
The final boss' name was Ouroboros, based off a snake that ate its own tail and symbolized eternity... or something like that. I don't really think the boss looked like a snake, but his ability did match, I guess.
The FF in the title was really well done. No, not Final Fantasy, but when you take out the two FFs, you get...
The two first forms are pretty... disgusting. She? goes "Hahaha, it's me, Airy!" and I'm all like "Oeeehhh~~!!"
And after that, here were the characters as I defeated the final boss.
Obviously, her main job is to heal. Doushi allows her to use less MP, though Doushi's skills were not so useful in the final battle. However, Doushi's abilities are plenty strong.
When she is not healing, she uses Attacking Items or Holy (Strongest Holy magic)
Bare's move "Copy" is very useful when used with Super Star's "My Boyfriend is a Hero" (Super Star Lv14), because Copy only copies the move and target, but not the cost. So with a payment of 2 BP and Full Brave (=5BP), he can boost the entire party's BP by 4, which can cover part of the cost to do this combo too.
Actually turned into my strongest attacker after I discovered the combo with Iron Defense (Knight lv4). Her classes mainly were ones that fit her, such as Knight, Sword Master, Dark Knight, etc.
Iron Defense to Super Takedown (Knight lv14) does 9999 damage, sometimes to enemies Defaulting! But the cost of Super Takedown is BP1, and to do a Full Brave, she ends up at -3BP.
However, that is why her main class is Holy Knight. Holy Knight's Death Pallet(?) (Holy Knight lv12) does the exact same 9999 damage without any cost. Full Brave allows her to deal 9999 x 3 and combined with Super Star's Copy combo allows her to use this 9999 x 3 combo two turns in a row.