Objectively the game is probably a 7 or 8/10. The gameplay is servicable; a bit of bullet hell mixed with platforming. The story is relatively simple but very heartfelt, with character interactions being the driving force for storytelling. The lore is interesting enough and sets a good setting. The graphics are simple even in most battles being just 2D sprites that either have a handful of frames of animation. There's some clever programming that can lead to a few surprises provided you do just the right things or are lucky, sometimes you'll have inconsequential random events pop up that you might not see on another playthrough for instance. There are multiple endings, 3 main ones and small variations within them. The soundtrack is definitely a 9 or 10/10 though.
In my very biased opinion though, I give the game a 10/10. It came to me in the perfect time of my life and I think I'm the better for having played it. I love the characters, the interactions (including battles), the lore, and the music all as a whole, and no part of the game would be the same without the other.
It's a niche story and character driven RPG with bullethell elements and, if you get the chance, please play it.