Ian
As a foundation for things to come, you have built well. As it is now it needs some embelishment. You plan to experiment with vocals, and drum parts. this will add the needed direction that is now missing. I think that 5:05 might be just a little to long. You might try to trim it to around 3:50 or so depending on the vocal track. I am possessed by the sound. The current percussion goes very well with the strong synth waves but tends to be to predictable after a time. I think you will change this as you progress into a final composition. My final thought; I like it. It has, or should I say, you have potential. Well it has potential too. I have put it into my mp3 library and will be looking to see what becomes of it. Best of luck.
Majik