Hey man. I like those songs.
Buried Alive could do with better drums, bit more bass drum and more aggressive snares along with the guitars.
In terms of tweaking it, have you though about putting in some simpler bits rather than making them more complex? I like a cut to just drums for 2 bars / add bass for a bar / 1 guitar in on bar 4 then everything off again. Layered guitar intros are also good, where you have one guitar doing something simple and another one building on top of it until you both shoot off at full tilt.
Basically, thrash arranged like AC/DC :) Did I mention I quite like them? :roll: