I'm tuned and everything, but it still doesn't sound right. Its not as edgy or <i>brutal</i> if you may, as in the song. I know there is multiple guitars, but the single parts don't sound right. Are there tone/bass etc. settings I need to tweak to get it right?

My guitar currently has about 8 month old strings on it, but I haven't been playing a lot. I plan to change them soon anyways.
It might be the strings even if you have played them or not 8 months is a balls load of time.
...and the world sighed in relief
i just max out all my knobs, tone, distortion, etc.
now i just have to play it right.
the tuning can be tricky, make sure you have that.
Satan isn't inside a guitar pick. He's in here. In our hearts. He's what makes us not want to go to work, or excercise or tell the truth. He's that little voice in your mind that says "Fuck you" to the people you hate.
check your intonation
I know I'm tuned right. Everything sounds right, except this part:

Rhythm fill 1a
C ||------------------------|
G ||------------------------|
Bb||-----------7h8p7p5----| X4
F ||-------7---------------8-7|
C ||-5-5---5---------------|

Tabs a little warped but thats basically how it looks. Anyways, when I play it, it sounds off.