Badass Riff

Ok so i have had this riff since like highschool or something, but it was always played fast, like some rockabilly song. I got the idea from watching the metallica dvd of the black album to play this song slow. You see, the song "sad but true" a slow, huge, heavy, song was once played really fast which made it sound like a happy fun rock song instead of the badass piece that it is. So i had the same problem with my song. I always thought it was too happy and fun. So i slowed it down, and it turned angry and now i think its rad. I dont think i even played it slow enough yet. It could still be slower and more angry. check it out.