Brilliant...
Well, I must say this is an awesome piece of music.
I really like it in general, and I think it's just awesome, there's nothing I can really say to either give you advice OR to improve it, the only 'improvement' is to submit/make the whole song.
Seing as you made the whole song by yourself, that is VERY impressive, I really believe if you were to submit this to a record company that would not turn a blind eye on it.
Well done, and good luck!
- Omega-Weapon