Implemented MSAA (multi-sampling anti-aliasing). Comparison screenshots - open in fullscreen:

No MSAA (285 fps):

4x MSAA (222 fps):

16x MSAA (93 fps):

4x MSAA + FXAA (178 fps):

Old anti-aliasing method used in SE - FXAA - is still usable. It gets better results when used in combination with 4x-8x MSAA than using pure 16x-32x MSAA. And performance hit made by FXAA is not that significant.