(this is just criticism, i'm not trying to hate)
first i'd like to give credit where credit is due. you made this on scratch. that's insane, props to you! for a fangame, it is quite difficult for me! that may just because i'm a beginner at rhythm games, but i liked how challenging it was. it was an acceptable amount of difficulty, and i enjoyed playing it.
the overall quality wasn't too great, but it makes sense for a scratch fangame.
i'm a new touhou fan. i haven't played any of the official games yet, but i do think this has room for improvement. the main aspect that i feel needs to be improved is the artwork. i understand that art isn't the easiest thing in the world. i'm an artist, and damn, is it hard. but tracing art? not the best decision ever.
now i would be okay with it if the original artist was like..... making a base for something and just required credit. but there was no base, and no credit. you simply just drew over someone else's artwork, and that isn't okay. i'm not going to yell at you for it, i'm just saying that you need to do better.
if you aren't going to draw anything, please just use a base and credit the base maker. using bases with credit is actually a genuine way to start doing art. eventually, when you're comfortable with using it, you can move on to broader things, like sketching and lineart and coloring etc. etc.
i would also critique the character design but learning character design is an absolute pain in the ass. maybe just don't use such extreme colors for now.
the music isn't well... impressive. i don't know too many touhou songs, but i wasn't really into it. it's fine, there's nothing horrible about it, this is just a personal opinion. i don't feel like i have enough experience to discuss this, so moving on.
overall it's mediocre. it has potential, but definitely lots of room for work.