This game is kewl, but I remember DawnRaider was bit better. It had a cool super-beam weapon that required you to press and and hold a button for some 30 seconds before it fully charged up. And you could play coop with a friend sharing 1 keyboard. DR didn't have many weapons, only 1 that could be upgraded like 30 times until it reached it's full potential.

Just loved that game and its Demonstar sequel. The game is not really that hard, since I got the MKS version.

This is one of the best shoot 'em ups on PC.
I remember that on some special date (don't know which), the sound of apogee is changed, propably some easteregg.
I now have this game on iphone and it's cool, there's also windows version!

It's the 16th of May, there're also some easter-egg extras. See here.