Well, as far as I am aware 16:10 usage is, unfortunately, far away from "common" and rather considered as "insignificant" in gamedev. Even big gaming studios rarely support it, so it would not be a surprise that small indie teams and solo developers didn't have any resources to allocate for 16:10 support either.
Did you run the game on 1440x900? How does it look? Is the UI broken, is it stretched, or is it just fit into black stripes? I never had a chance to deal with native resolutions outside of the 16x9 so I have no idea how it works