Working with SVN build 12520, starting with my USA games first...
First, the bad news:
Dark Savior, Nights, Virtua On, Panzer Dragoon Zwei all used to show some graphics (or more), but now they immediately revert to the Saturn Console.
Other people are reporting success with World Series 98, but mine freezes right after the first little loading disc shows up. This used to allow me into the menus.
And now, the good news.
Daytona USA is working. I think that was already mentioned, so I'll forego the pictures.
Ultimate Mortal Kombat 3 is now playable, although graphics issues arise after you are uppercut into a new level (see pics 3 & 4).