i checked out ur second one, but as many people have pointed out in another thread im not the biggest fan of heavy opeth so maybe you should disregard what i say
i found alot of those phrases with straight power chords got kinda boring, as did the thrashy sounding low e segments. i saw some 6ths in there too to be fair, but imo power chords and octaves they get boring fast - especially since they are in pretty much the standard positions (most of the time). my advice is, maybe try changing it up and adding some less used chords, you could try using a sus4 chord which sounds kind of evil, or a diminished triad and take off the root for better switching ease. maybe try inversions (works alot better in triads than in power chords.) but yeh, just remember im not a big fan of power chords in the first place, so instead u could maybe change the position around or add in some tensions to the chord?
i thought the string skipping section was nice, maybe a little too high tempo but still sounds good. are you going to put any leads or solos in?
sorry i skimmed through it quickly, i dont have very much constructive information for you other than that