I have no idea what the spirit tracks overworld sounds like, but it's not too bad. Most of the problems are in the mastering of the track.
Tone down the shaker, a lot. That hurt my ears. It's just way too jarring, and it since it only keeps the beat, it has no need to be so prominent.
Also, the main pipe synth melody needs to go down in volume. It sounds as if you've got the note velocities set a lot higher for the high notes. That's completely opposite of what you should actually do, because high notes have a tendency to naturally push through the mix you should actually lower their volume a little.
It's all there, just needs a little more work. Hope this helps