First post, by Glidos
I broke something in the last release, so I've just uploaded 1.55 with a fix.
For most use, it's best to select psVoodoo, Full screen and Inhibit mode change. That will ignore the resolution you select and use the largest 4x3 subarea of the screen that fits. That was the mode I'd broken, but it now works again.
If on the other hand you are trying it out in VR, in the way I described in an earler post, then uncheck Inhibit mode change, and select the highest resolution your monitor can handle. (You can type in any resolution now, not just select ones from the dropdown list).