not bad
But it could use the following tune-ups: quicker movement(both you and enemies), less annoying foot tapping, better controls, more explinations concerning how enemies attack( several enemies seemed to glitch on me and sort of tractor beamed you so they could bite you, while not being close to them in the process) a new and improved revamp of the HORRIBLE audio tracks used in this game (The original audio would have worked quitew well, considering the fact you used the copyrighted doom 3 theme anyway)
AND MOST IMPORTANTLY: how many people do you really expect to join that stupid site so they can get what is already in the game? I would think that with so many demos out there that you guys would give up and realize that the vast majority of people who play those demos, will NOT pay money so they can enjoy a poorly graphic game when they have shit like xboxs and so on so forth. Just implement the full game the first time around.
Awesome doom game overall, just quit posting basically demos on newgrounds!