AGS seems to have that fixed since 3.3.2 (September 2014). The resolution selection code there is much more robust and it supports both letter- and pillarboxing.
@omicron-b indeed it's option 1. This problem most likely would be present on Windows with that monitor. Thanks for the confirmation! I think it may be time to add a bunch of common <= 4K resolutions to fshack to make li...
The game is built using the open source [Adventure Game Studio](https://github.com/adventuregamestudio/ags) v3.3. Luckily for us it logs a lot of info using `OutputDebugString*()`. The game uses 320x240 native resolution...