Very nice game.
Even nicer that I spotted my name in scrolling credits!!
I've played it up to level 11 so far and it starts to get a bit manic by then.
The only downsides I have found so far are the lack of instructions as to what keys do what. Took me a while to work out even how to shoot, even though you exlained in top post. Maybe a controls screen and a readme file would be nice.
I also think the way the game slows down to a crawl if I hold fire button down is a bit offputting.
Can you also explain what the information panel at bottom right corner is supposed to tell you (something about fire,down,test??)
Nice to see your little demos turning into fully fledged games.
Boo!