Just finished it, had to come and throw in some more love here in hopes to raise awareness about the game. Complete blind purchase, I almost didn't know about the game before it was out and only was reminded of it thanks to this thread (so... thanks!), and it turned out to be quite the experience. "Fever dream", indeed.
I almost hated having to turn off the game occasionally, actually, since the battles are so reliant on being in this highly specific groove that coming back after an extended break always led to my most difficult encounters. Thankfully, you become so overpowered by the end that even the end boss when fully upgraded is more about the symbol it represents than an actual challenge :-D
The boss that gave me the most trouble is probably the second one, because I didn't swipe fast enough to stop him from swallowing anyone. Had to fight him a couple of rounds with multiple buffs at the same time, but still made it through somehow...
Anyway, yeah, if you're a Vita owner unsure about this, this is the kind of game you're not likely to find anywhere else (unless they decide to port it to mobile or something, but even then, lacking buttons, it'd not be the same). Kinda wish we had more games that took full advantage of the console's ergonomics like this, but I'm glad the precious few we have are that good!
GJ Drinkbox, very much looking forward to what you come up with next!