You've got to work on the synths...
OK, I want to be as constructive as possible here, so don't take what i'm about to say to be cruel or bitch.
Firstly, I think you need to change or at least soften up the synths at the beginning. They sound too harsh and definitely under produced. Maybe adding a little reverb to them with some chorus and get rid of some of the higher frequencies.
The beat in the beginning is alright. But I would suggest padding out the kick if your really looking for that dubstep sound. Just boost the lower frequencies of it and it should thicken it out a bit.
I really like that subtle beep sound playing the melody. It's nice and eerie and carries the rest of the piece well.
So on to the bass. It is OK. But OK can be greatly improved. I would suggest at least adding a sub-bass underneath to really give it that chest vibrating feel. I'd probably suggest also playing around with some reverb on the main bass synth as well.
All in all it's a very strange piece. I would really call it dubstep, but then again i'm not sure what I would call it. It's not bad by any means, but it does need alot of work on it.
Hope the review was helpful, James.