I love how unassuming the intro is, like, "Meh, this might be okay.", but then BAM, RAAAAAAAAAAAAAAAAAAA!
The main riff was simple, but in my opinion, primal and driving. Which is exactly what you want in metal. My only real complaint here: It was not long enough! I was expecting a full song (not seeing the length of time it was) and was disappointed when, right when I thought it was the middle of the song, it ended.
Extend the song, add a little bit, and you'll have a serious metal hit!