[zerofrog]

It looks like those gfx problems are due to imprecise floating point arithmetic. Both ATI and nVidia have their own unique way of taking floating-point shortcuts (for example, 1.501*2 will probably be 3 instead of 3.002). This especially occurs on older cards. I'll see what I can do about it, but I think you should invest in a new video card.

For now if it isn't too much of a problem, you can resolve the fullscreen problem by setting your desktop to 640x480 before going into full screen. And aspect ratio is always preserved in zerogs.

EDIT: what makes your games slow isn't the window size, but the frame buffer size. Whether you have 640x480 or 1152x768 shouldn't really matter (from my tests anyway)