Maybe you need more bios, try mame bios aswell, similar with kof2002, gngeo returns a error message like 'something really wrong happened' don't remember, but the app recognizes rom, then crashes before load. Some bigger roms require to dump .gfx file to make them smaller, so gngeo can play, it is called WinDump or so (for Windows systems) , but I haven't tried that yet. You get screen small because you have OS2008 version installed. Will try to make a small tutorial tomorrow or later. And a video on Youtube.