Well, "non buffered" rendering is a hack where we simply skip all rendering that's not to the main display surface. So yeah, not all games will work correctly with it.
It's possible to imagine some "hybrid" mode where we render stuff to the main display surface directly to the back buffer, and other surface to FBO instead of skipping them, but that's a bit of work and probably won't help speed much.
It's possible to imagine some "hybrid" mode where we render stuff to the main display surface directly to the back buffer, and other surface to FBO instead of skipping them, but that's a bit of work and probably won't help speed much.