don't remember seeing this. If you're still interested, I'll do a critique of your Goodbye under the Cherry Blossom.
You seem to have a knack for coming up with pretty catchy themes, almost every thing in this one is catchy, the ones in the other 2 are also pretty good as well.
It does, however, feel like you're simply improvising at the keyboard, so to speak. I'll show you what I mean, here's the structure of the piece:
A B A C
(key change)
C A B'
(key change)
D???
(key change)
A C C
It doesn't make any sense. It's hard to tell what's about to come next or what came before it. The themes themselves, while catchy, mostly follow a similar harmonic progression with the same harmonic rhythm in the same key, so they become a little blurred in memory. They also share a similar mood and there doesn't seem to be any hierarchy between them, so it's even harder to tell 'where' in the music we're at. As an example, bridges and other transitional passages have a role in their music which is to pass along the viewer's attention from one theme to the next. ZUN uses this a lot too, he tends to make them less melodic and somewhat repetitive to draw attention away from itself to inform the viewer that the important theme is the one that's about to come next. It makes the main theme(s) that much more memorable since you have a small break between it's appearances.
So that being said, while improvising at the keyboard over a certain harmonic progression can get you numerous acceptable, even good, themes, you should limit yourself in not having to use all of them. Or, to arrange them in a way, give the music structure, so that the listener can comprehend your intentions.
Ok, so that's the general advice. There's two more places that are a bit odd. The first is at B'. At first I thought it was a completely new theme since we haven't heard the B theme since 5 themes ago, which was even its first appearance. But anyway, you work so hard at the end there to climb to a new key which do you finally land on at D. Which leads to the second place of oddity, D. It's completely new and so it's pretty easily to lose track of what's happening, but I've said something of that sort already above. The thing is, it's super short. Before it even has a chance to do anything or lead anywhere, it just wanders off and gets cuts off mid-speech. And then you key change again into the last A theme. All that work you put in to changing from the key at B' to the new one at D is suddenly tossed aside. It seems like such a waste of effort, and even kinda makes the point of B' like "what was the point of that?" kind of way.
I think that's all I have to say. I was immediately hooked though, you have that going for you. Keep trying and keep at it!
e: to give a more concrete opinion, I think it would do the music a lot more good to, at the very least, cut out theme D (and the key change following it) and maybe even the last A theme.