Mix + Master challenge

[Protoplanetdisko]

Guys,

I wonder if there are any tips to improve the mix + master of this track - http://soundcloud.com/protoplanetdisko/anonymous-demo

I tried redoing it, but seem to be encountering the same issues with frequency using the Izotope mastering software. The mixing part of the process may not be helping either.

I had to compress the available version a lot.

Any tip is highly appreciate.

Thanks!