The Mac OSX version of the game is now available:
http://www.suisoft.co.uk/starfire/
The gameplay is the same as the PC version (i.e. hard).
Next I will work on the difficulty settings to make the game more accessible and also look into the performance problems on some machines. I suspect the performance issues come down to the nebula rendering and screen resolution.
Feedback appreciated.
I'd really like to know how many people think the difficulty is reasonable and how many think it's too hard. Bloggers seem to think it's about right whereas forumites seem to think it's too hard.
For players wanting a challenge try out the 'Hardcore Mode'. This switches on 'one hit kill' (i.e. enemy shots kill instantly). I have beaten it on normal, so it is possible. It just takes extreme teeth-gritted concentration and significant practice and patience.