Finally played all the songs in the Quest mode so I think that it counts as “Completed”, even if I'll probably keep playing this for a long time.
This is a nice entry to the series! I've been a Theatrhythm enjoyer since the very first vanilla 3DS game and I'm always happy to see that it's still alive and kicking. I feel like Final Bar Line is a clear case of “You Win Some, You Lose Some” - there are TONS of new characters and songs (they listened to me specifically and put more Mystic Quest songs in there), as well as new cards to collect and such. And the colours and light are so beautiful!
However, some of the charm from Curtain Call is lost in my opinion. I feel like this game took a step back for no reason when it came to stuff like the world travel songs - now the backgrounds of the worlds (although NOT during the battle songs, thank god) are all different kinds of standard world/cave/town/whatever areas that are juuust generic enough that they could fit into any Final Fantasy game, rather than the charming backgrounds in Curtain Call which had different landmarks and such depending in which FF game's song it was. I get that they can't make a customized background for every single area in Final Bar Line but it feels kind of like a letdown that they didn't even bother making a cute little world to travel through for the main titles as they did in Curtain Call, when this is supposed to be the newest, freshest, most content-filled entry yet… Sorry I keep harping on about the backgrounds, they were important to me. I also feel like the collectibles were a bit more interesting in Curtain Call, with the small descriptions on the cards you collected and such… if I'm being REALLY picky I also feel like the little level up-quotes by the characters were funnier in CC, here they feel a little generic to me. And why does my guy Mr. Mog FF6 only say “Kupo”?? His whole thing is that he's a talking moogle… oh well.

BUT as said, despite these things, this is a really fun game and I adore all the new music that was added. Even from really obscure titles!! And I love the addition of character-specific special moves, and the unique little handcrafted song thumbnails that respresent story moments in the games where those particular songs are playing is probably my favourite addition yet. The gameplay is great and I'm currently leveling up all characters to lv. 100, haha. I hope that when the next entry is released in 200 years it will have this amount of content AND increase the cute fanservice things that were scaled back in this entry. If squenix should know anything, it's that probably 80% of their fanbase (me) loves cute little nods to the series and meaningful collectibles.