What a goddamn disappointment of a game after the fantastic Ar Tonelico II. It's not.. Tremendously Bad. It has some good spots: The battle music system is actually unbelievable in how varied it can be and I recommend reading about it on the gamefaqs forums ( https://gamefaqs.gamespot.com/boards/976762-ar-tonelico-qoga-knell-of-ar-ciel/59004818 ) , the end of Finnel's cosmosphere is pretty raw (some of the only rawness in this game, honestly, but it's dragged down by how it's not treated as seriously as it should be in the previous levels), I like the 3rd reyvateil and her backstory. But so much is a severe downgrade from AT2 it's hard to overstate.
update: my opinion has turned very slightly because i've thought about the final boss fight more a while later and holy shit it is so fucking raw and the song is ACTUALLY peak. It's such a departure from the less than stellar rest of the game.