Not in this one, it'd be too hard to add it in. So I'll write it in a txt file instead.
But the next game will have a music room when I get there.
Danmakufu and its problems! I can't guess why it won't run properly for some people. There's no Japanese text in it, which usually causes problems. Hm!
As for the difficulty, am I the only one who easily has 3+ lives left at the end on Normal? I consider this game easier than UFO, maybe SA level. Even if I know it by heart myself, I'm not that good at danmaku games. Now Extra and Nightmare are tough (maybe Extra needs more nerfing). But still, beating a shooter game on your very first attempt is pretty boring. It has Easy mode and Spellcard Practise for a reason!
Tree of Life has a very big "bullet delay" 
Dancing Furin is one of my least favorites. Just like Mai herself.
Which type(s) did you use? Don't say Fire only.
To be fair on the count of the difficulty, you did
make the game. I remember a good quote from Extra Credits about this sort of thing "If you (from a developer perspective) think your game's difficulty is just right. It's probably way too hard".
I don't think the increased difficulty is a bad thing. Since you've got unlimited continues it's not something I mind terribly much, just something I figured was worth pointing out, it's difficulty curve is much steeper than that of a regular Touhou game, not implying it's a flaw that needs to be corrected. Just that it makes the game less accessible to people not well versed in bullet hell shooters, although granted, given that you have to find this game through the forums of a fan site for a bullet hell shooter series, I don't think that's much of an issue. :V
For stages, I primarily used Wood type since more points = more lives, right? Seemed like a good idea on paper.
For bosses, yeah I did primarily use Fire type. Sorry, not really sure why you're a downer on the Fire type there, is it because it's the type everyone uses or something? The deathbomb timer makes it nearly impossible to waste bombs (
unless you get blind sided by aforementioned two third of screen kill cards) and is thusly good for survival. It's like Border Team from Imperishable Night with that deathbomb timer.
Since Fire makes it difficult to actually lose bombs, I never saw much of a point to using Water type and for the stages, since Wood generates more points and that directly translates into more lives I never found a good reason to be using Metal. And Earth slows you down... sounds like kind of a crap special ability if you ask me, that sounds more like a downgrade than anything.
The above was just my initial reactions to the varying shot types, further playing might reveal more interesting uses for the varying shot types since I can switch between them on the fly (which is a fantastic idea by the way). Just giving you the feedback of a first time player to the varying shot types.