It's hard to hear the frequencies of the sub bass. Maybe with some effects like a tube, a crusher, an exciter or a waveshaper would make it much fatter. You could also take out the highs if there are any with an EQ. If there's some really muddy low-end frequencies then I would some of those out. I'd say the really harsh frequencies you should analyze and reduce. But that's what I think about the song. Good work with the sound arrangement, and also the sweet variations as well.
