For some reason it's using the additional space to draw some sort of debug title menu with a "Test Mode" option on the right, and a line on the left. None of the menu options are clickable, however. I've tried fiddling around with the Xanadu config menu and the Nvidia settings menu, but alas, I've not been able to get them to disappear.

Not as huge deal. It's an old game and I can manage to play it in widescreen, but I'm hoping this is just some weird issue on my end and that there's a fix for it.