Please offer some advice.

5:4 (1280x1024) is the only resolution where the game works correctly; others don't. Ideally, with this resolution, it should fit with a small margin on a 16:10 monitor (1680x1050) and a 16:9 monitor (1920x1080), but it automatically checks the "Full Screen" box, and the game stretches horizontally. Is there a small margin between the game window and the screen? I didn't have a 1400x1050 (4:3) monitor to test this, but I didn't have this problem at all with 1600x1200. I think it's related to some simplification of the screen matrix. When widescreen monitors started to develop and were heavily promoted, claiming that the wide format was convenient for the user, they were blatantly lying – in reality, it was convenient for the production technology. A wide monitor is good for watching movies, but not for working with documents or anything similar.