Baseline (Widescreen) Solution & Issues
Game only natively supports resolutions up to 1600x1200. FOV is very low.
You will need a hex editor for this:
640 (80 02) [offset 13D38] is the width, and 480 (E0 01) [offset 13D40] is the height.
Replace
80 02 00 00 C7 44 24 20 E0 01
With (for example, 1080p):
80 07 00 00 C7 44 24 20 38 04
See http://www.wsgf.org/article/common-hex-values for other resolutions.
Make sure videoMode is set to 0 in <gamedir>options.txt.
Ultra/Super-Wide (21:9/32:9) Specific Solution & Issues
Same as widescreen, except FOV is even worse.
Eyefinity / Surround Specific Solution & Issues
4k UHD Specific Solution & Issues
Stereoscopic-3D Solution & Issues