I liked, It has a nice power that goes well with the vocals.
I would suggest to things, make the mix a little more interesting adding some movement with arranges, little variations, etc. If you want to use guitars and only have that “slayer” sound, use a little room reverb and cabinets if your plugins has it, a guitar never sound that “sterile”.

… What DURDEN said.

I do like the phatness of this mix though. Has a real intrusive and dark edge to it.