honestly, the drums are the only thing that need work. Live drums are hard to fake, but if you get some oneshots of the same instrument (one accent and one normal) then you should be able to articulate metal drums pretty well. Cymbals are where it gets tough. That's all automation in the pitch and velocity.
Besides that, you've made a TASTEY riff
I'd give it some crazy disortion on a parallel channel at
1:48