The kick and snare could use better side chaining against the FM bass, because they start to fade into being really quiet. the melody and synth for it is amazing, and the FM bass itself is pretty good. the reverse cymbals could be a biiiit louder, because they are an important part of transitions.The volume drops are kinda randomly thrown in there, never specifically with one part on the pattern, and that's kinda messy and lazy.
Overall, the mixing is pretty good with the piano and the other elements (other than the ones I listed), so it gets a strong 4. I added .5 because you don't see a main bass as an FM bass, and thats pretty creative. Reminds me a lot of rSeamless.