Not bad
First off, the last guy has obviously never played a real shooter before. Games such as R-type, radiant silvergun, einhander, raiden, etc, are made to be extremely hard and cheap. It's a design thing. Having said that, this is pretty good. My only complaints are the single stage, one boss, no powerups or different weapons, and last but not least, not hard enough. Up the difficulty, add some more bad guys, and a few more stages, this could easily be flash of the week. I'm sorry to hear that you won't be doing any more. This shows something really solid for a one stage flash game. I look forward to your next work.