You're not playing the riff right - not that it matters. Good job of mocking it, but not dead on.
The rhythm section (programmed I guess?) doesn't move right - the groove isn't there. The drums especially are choppy sounding. They need a more human, groovy feel.
Not to be critical - you're a good player, but when you attempt to pay homage to a master, you have to know you're going to get some critical feedback.
I've heard many guys try to cop that riff - some get close, but I have yet to hear anyone who plays it right (including myself).
I wouldn't worry about doing the riff note for note, but I would look at redoing the rhythm section and trying to humanize it a bit.
Good work though. Keep it up.