How difficult is Call of Ktulu?

I consider myself a decent guitar player. I’m self taught and started on acoustic with of course the basics, then some fingerstyle types, but recently I’ve been getting back to my metal roots. Call of Ktulu has always been one of my favorite Metallica tracks and I decided to try it out.

The intro has been kind of kicking my ass with the awkward finger positioning and that got me thinking, this is a good benchmark to see how far I’ve actually made it considering the amount of time I’ve been playing. So, how difficult would you say Call of Ktulu is to play?