I've included the DxDiag report and graphics report.
The game is freely available at openra.net, which I've linked in the original post.
To reproduce the issue, simply run the game on Intel HD Graphics 4600 using the latest driver (10.18.10.3907).
I have troubleshooted by loading an earlier driver, which works. Of course, I want to use the latest driver.
The exact game name is OpenRA. Again, it is freely available at openra.net.
I suspect I'm about to be told to use the previous driver, but I don't really think that's much of a fix. I told myself I'd be happy with Intel HD Graphics since the only game I play is OpenRA. Unfortunately, the one game I want to play doesn't work.