Its a bit tough to 'critique' so to speak, this, because my comments were just based on my expectation for this sort of style, which is based on neurosis, old man gloom and to an extent crowbar (you sound like a cross between the 3, musically, to me). You didnt do anytihng *wrong* or *badly*, imo, its just taste.
But as far as that taste/expectation go, I find it as I said...lacks density and intensity. Have a listen to Neurosis "The Doorway" and Old Man Gloom "Sleeping with the snakes". They each have a similar vibe to parts of the vibe of this and they each have intros with just one guitar so you can hear it. I think, a bit more gain (dont overdo it though), a little less in the 400-ish to 900ish 'mids-mids' range, a bit more in ~1.5 to 2.5k for more inyourfaceness and bump the 120-250 meat range and mesh it more carefully with the bass (which is good btw).
Just suggestions, feel free to take or leave. I often hate people on the net giving comments on my work thats basically what they want it to be, not what I want it to be, and have ruined mixes trying to please other people; do what sounds right to you, but the above is my advice.