Well done man, I think this has potential!
I understand that this is a demo and from reading your comments, I understand the faults I may encounter have already been acknowledged by you.
-Great music choice!
-Good variety of weapons! (Love the flamethrower)
-Great stage design! (Cyberspace etc.)
-Enemies are cool... (Nice electric animation on them!)
-Without being able to win/lose, this isn't much of a game... (Obviously, you already Know this)
- The font is a bit on the small size during the gameplay and within the 'How to Play' section.
- Just overall, needs more time spent on it...
It's the best start we could possibly ask from you, I believe. This is your first proper flash game and IMO, you on the right track as of now...
Keep working on this man, take in my criticism and hopefully, we can see a complete game in the future...