Nice riff and progression from the start - cool stuff, nice style - kind of retro while still being original. You planning on adding any other voicings or keeping it instrumental. I could imagine some nice subtle lead (nothing shreddy) with a very unique experimental tone adding a textured melody. Don't think it realy needs drums - but some electro percussion sounds (subtle ones like Orbital) could make those riffs sounds very cutting edge. Just imagining where things could go... what you planning to do with it?