It is spectrally sound. Not bass-hyped, a frequent symptom of headphone mixing. Pretty good balance of instruments and frequencies. Not overcompressed, good dynamics. So on a technical level, 4 out of 5 stars.
Compositionally, I'd agree with Warren's assessment: as a standalone piece of music, it takes too long to get to the meat. What I'd suggest is throwing in some ear candy early on, perhaps some high percussion to float above the long drone at the beginning. and add some interest for those with short attention spans. Maybe just bring up that little rhythmic (flute?) part that you've already got going there.
My rule of thumb: let no phrase go more than a measure without
something changing. It can be a subtle shift of emphasis, automating EQ or reverb, adding a new voice, muting an existing voice, adding a counter melody, or tossing in a triangle. It doesn't have to be a big thing.