Baseline (Widescreen) Solution & Issues
jackfuste made a hack which displays the widescreen resolutions correctly. Download and copy DTRPC.exe from files available from the PC Gaming Wiki Community Files (search there) to the game folder. Widescreen resolution you can choose from the game menu.
To increase the FOV open settings.cfg from the game folder and add to [display] section the following strings:
hfov=25
vfov=25
0-99 - possible values for hfov and vfov.
You can also download and copy to the game folder settings.cfg from attachment.
Ultra/Super-Wide (21:9/32:9) Specific Solution & Issues
Eyefinity / Surround Specific Solution & Issues
4k UHD Specific Solution & Issues