Let me know what you guys think.
Your sub is very loud in the mix. I think you should take everything to zero and level it out without a limiter; as it stands, every time the sub punches you get a pretty noticeable dip in the overall levels of the track.
I like the pads and atmospherics in this a lot.
Perhaps one more element/variations of current elements, I feel like just having the piano come in and out is a tad boring. Like even with some of the pads, adding some kind of stutter/rhythm changes could spice things up a little. Could also go with some bleeps and shit too, just litte bits here and there to regain attention. May not be bad to do some automation on that arpeggio either, make its intensity in the mix vary it at certain points.
It could also just be something percussive, like rides, or a new dominant hi hat loop.
Snare could maybe use more top end; if you agree it could be good to layer what you have with some white noise. Mid/high freq. reverb on the top end you do have could help hold it down more too.
You playing these drums in? The kick rhythm is interesting.
If you layer another sub with LFO on the volume under that wub you have, it could punch a little more on speakers. That said, it’s late here and I’m not trying to piss off roommate/neighbors.
Piano loop is pretty dark, props on that.
Also peeped Jupiter, that one goes in, lad.
yea everything is definitely getting lost in the sub, @Stuff_iain_ttryingto is pretty much hitting the nail on the head, in terms of variation, the ‘sub-volume lfo’ and ‘snare-white noise’ techniques are really effective 
Try some gain staging in your mix, i.e. all faders at -infinity (muted), start with the kick, get it peaking around -9/10db than bring in the snare until it sits with the kick and has a nice punch, then the sub (peaking around -3db less than the kick works well), and then each separate element, in terms of ‘importance**’ in the final mix.
(**Think about what role each element is playing in terms of tone, timbre, texture, movement, melody etc. hence kick/snare first as this is the back bone of the whole track, you might bring in the hats before the sub to hear more movement in the beat).
Track all in all’s got a really nice vibe, love the metal style kick pattern 