The piece is fine perhaps a couple of odd harmonic moments but perhaps that was intentional. The issue is really ONE BIG THING…the sounds. Your instruments sound like VI’s from 10 years ago. Then when you take older and dated sounding instruments and put them in a medium to more smaller room setting it exposes there “fakeness” even more. You need to invest in better sounds and then learn how to orchestrate using Virtual instruments in an effective way. If you are going to have a minimalistic piece like this you better have quality sounds since everything is so exposed and you better know how to use them.