Nice piece, good melody. I think that it could do with some kind of variation in the middle to take it in a different direction for a bit. I always try to either change the key, timing and or rhythm to add some colour. I like the track but I wouldnt stop there with this one. I would add a solo in the middle and a few short licks every now and then to add another voice to the mix. It has great potential and sets the background tone for some nice lead work. I hate vocals in music, so by all means leave them out!