It sounds quite nice. On the other hand, there's no melody until about 3 minutes into the song. Until then, we have a melodic line that's only an outline of the harmony (ZUN uses these a lot in transitionary passages, a good example being Native Faith). So nothing that necessarily grabs your attention. The melody is fine enough, the melody itself anyway. But it's a little too elaborated and restless, it doesn't want to stop and rest and let me know that it's the melody and not just some fancy running pianistic figuration or improvisation over the harmony. I would suggest that you take the important notes of that melody and let the rest sink into the back a bit or mix it off to the side somehow. I keep thinking the melody is going to stop around 'here' somewhere but it keeps continuing wandering around until it comes in again in the next phrase. Silence is a good thing, it helps to let the listener know the breathing of the melody, the comma in the sentence. Question? and Answer.
As an example, in that third measure from where 3:13 starts, where it goes C#-BD, bah→→ba↓dum↑, everything after that D, that third beat on the third measure of that phrase until the answer comes in on 3:19, I would suggest either softening that passage to put it further back from the foreground or putting it in another instrument or leaning it towards the left or right channel or whatever.
I guess what I'm trying to say is that, right now your melody and countermelody are melded into one line and are indistinguishable. That and/or your melodic cadences could use some advice. To that I will provide this example,
Sleepless Night of the Eastern Country. The first theme, the first melody starts from 0:06. The first utterance of this melody ends on 0:12. It's made of two halves, two phrases, the first one from 0:06-0:09 and the second phrase from 0:09-0:12. Each of these phrases can be further divided into two short halves. Notice that the rhythm of the melody is the same for both halves of the first phrase, and the first half of the second phrase. Instead of following the same rhythm for the last half, the second half of the second phrase has a different rhythm. Notably, the melody ends early and the rhythm stops, as a sort of breathing point, a resting point, to let the listener know that this is where the melody rests and stop. That this is one whole unit and that the melodic unit ends here. After this short breath, ZUN proceeds to do a little scale run at the end of this last half to lead into the start of the new melodic unit, most of which is a repeat of this first melodic unit.
That was about melodic cadences, or resting points, you want these to form a coherent unit of melody. Silence is a good thing. As for countermelodies, we can still use the same song. The second theme comes in at 0:30. The first phrase of this new melody ends at 0:36. The actual melodic line stops at 0:33 and holds until the end of the phrase, but the countermelody comes in at 0:34 under a different instrument. This way, not only do we get a clear distinction between melody and counter melody through timbral--different instruments-- and registral--countermelody is higher in pitch-- differences, we also get to preserve that long 'silence' or resting point in the melody because it's being held for like two whole measures. The countermelody provides that aural interest by coming in during that long resting point without disturbing the restingness of the melody.
So currently, your example has no rest and the countermelody is being 'sung' by the melodic instrument, which, being melded together, ruins the melodic line. I hope I was able to elaborate enough clearly without sounding like a pretentious thing. I do like the overall sound of what you have there, just the melody could use some advice.