The improvements affect any OpenGL game, but I haven’t tried an Unreal engine title with the changes yet. IIRC the original Unreal was already working at some point, but I’m not 100% sure.
BTW: The OpenGL support is more of a personal pet project than anything else. It is still limited to fairly old (‘fixed function’) OpenGL games. I’m two or three steps closer now to a point where tackling G3D for newer, shader based OpenGL might make sense, but that may or may not happen, so don’t hold your breath. There are always more important things…