I beated this because I loved the models, flan taking off her hat was quite badass tbh.
But yeah, gameplay is broken, if you touch any edge of the screen, sakuya will start turning and knifes can end being shot from her back (NO WAY), so aiming is terrible when this happens, some bullets went suddenly still at times, so it need a little fix for some things, but visually is very nice, I hope you keep on on making more like this.