Standard tuning.

b = bend
h = hammer on
p = pull off
/ = slide up
 = slide down

Intro and verse (but without the "chugging" bit at the start)

e--x--x--x-x-x-x-x-----------------------------------------------------------|
B--x--x--x-x-x-x-x--3--3-------------------3-------3--3--------------------3-|
G--x--x--x-x-x-x-x--2--2-------------------2-------2--2-----------------0--2-|
D--x--x--x-x-x-x-x--0--0--3-3-3--2--0-0h2--0-------0--0--3-3-3--2--0--2----0-|
A--x--x--x-x-x-x-x--------3-3-3--3------------3h5--------3-3-3--3------------|
E--x--x--x-x-x-x-x--------1-1-1--------------------------1-1-1---------------|

Main riff (low)

e---------------------------------------------------------|
B--------6h8-8b10b8-6-5-6-5h6p5-3-------------------------|
G--7p5h7--------------------------------------------------|
D---------------------------------------------------------|
A---------------------------------------------------------|
E---------------------------------------------------------|

Main riff (high): Method 1

e-----------13h15-15b17b15-13-12-13-12h13p12-10-------------|
B--15p13h15-------------------------------------------------|
G-----------------------------------------------------------|
D-----------------------------------------------------------|
A-----------------------------------------------------------|
E-----------------------------------------------------------|

Main riff (high): Method 2

e-----------------------------------------------------------|
B-----------18h20-20b22b20-18-17-18-17h18p17-15-------------|
G--19p17h19-------------------------------------------------|
D-----------------------------------------------------------|
A-----------------------------------------------------------|
E-----------------------------------------------------------|

Bridge

e-----------------------------------------------------------|
B-----------------------------------------------------------|
G--5--5-5-5-----5--5-5-5--5--3-3-3-3-3-3-3-5-5-5------------|
D--5--5-5-5--5--5--5-5-5--5--3-3-3-3-3-3-3-5-5-5------------|
A--3--3-3-3--5--3--3-3-3--3--1-1-1-1-1-1-1-3-3-3------------|
E------------3----------------------------------------------|


He throws in a few embellishments along the way, but you can work them out yourself, or leave them.