We'll I'm not really sure but it sounds good.
You have to use a very hard distorsion to play this 
song.
It's very easy.

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 |-00000-121-00000-323-------------| 


Here it is. I don't think they are playing on the 2 or 
3 first strings because it will sound
too * if you want you can play this song like this:

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 |-2-2-2-2-2-3-4-3--2-2-2-2-2-5-4-5--| 
 |-0-0-0-0-0-1-2-1--0-0-0-0-0-3-2-3--| 

This is the main riff:I love it!!