Pretty good, especially in terms of presentation. but I think there's a few small issues that kind of could do with a bit of polish.
a) I don't mind the escort-student gameplay too much but as others have mentioned it could use either a minimap or an arrow pointing back to the safe zone. I can't say that it's very fun in and of itself though, especially when it is most of the game.
b) You can't get health back as far as I could tell, so it was pretty rough even to get hit at all, especially when you don't get full HP for the boss battles. Having to redo the whole escort section especially for Chapter 2 again if you get destroyed from the boss was kind of a pain. (Yes, I know this is ironic since my game doesn't have checkpoints yet).
c) It took me a while to work out the height mechanics; I don't think they're very clear without being explicitly explained, and I don't think the visual differences between projectiles is clear either.
d) I think this is sort of a common thing with SHMUP developers but it's very difficult to focus on dodging shots and shooting a small target at the same time, especially with how small the ghost girl's hitbox is.
As a bug, after I quit to the main menu while being in an introductory cutscene and tried to load a new level, I was unable to move WASD after loading (though I could aim and shoot).
Other than that, I really liked it! The Chinese-ness of it was aesthetically appreciated as well; my ma-ma gave me a jade pendant just like the one on the UI screen, and the music used and overall design of the characters really accentuated it all. I also especially liked the camera flourish on the menu when clicking start to begin.