Baseline (Widescreen) Solution & Issues
Native.
The game uses your desktop resolution by default. You can also pick your desired res from the launcher, or change it at any time from the in-game Options menu.
"Matte painting" FMVs are anamorphic, except in surround they are Vert- (although subtitles display ok). Some events trigger in-engine cut-scenes that are Hor+/Vert+ because the peculiar letterboxing hides less of the picture in wider ARs. (I for one wouldn't count this as a blemish.) In surround, Hor+/Vert+ (actually sth like "Hor+ with no letterboxing").
Ultra/Super-Wide (21:9/32:9) Specific Solution & Issues
Eyefinity / Surround Specific Solution & Issues
4k UHD Specific Solution & Issues