Loved it, agree with everything said so far, very original. You have put your own stamp on it which is fantastic to hear!
Harmonically and structurally this works really well, I enjoyed the lightness of the passages that were playful in nature. Reminds me of saint seans in some respects. The genre is changed considerably which isn’t a bad thing and you kept the overall feel of the melodic content quite grounded.
There were some things that I thought you could have payed more attention to, such as the transitions between some sections. A few cadential passages wouldn’t have gone amiss, this would have solidified your sections even more than you have done already, giving them a stron harmonic grounding. There are many ways you can do this. The typical ones are 5-1 (perfect cadence) or imperfect if played the other way around, plagal cadence (1-4), or you could mix it up a bit and have transitionary cadences that use a pivot chord, or substitution to transition to a new harmonic centre. Just some things to look into
Mix wise, the overall levels were quite good, though you could reference a track with the same mood for a tighter result, and the low end was interfering with some of the harmonic information… so a bit of subtle EQ could be utilised when the track gets going in the rich sections.
Really like this and I hope the feedback you asked for helps!!