erm , I understood the same as André.
So you want to keep the flat screen but put in a different game?
Make it Mortal Kombat then, this game deserves no better than a LCD-monitor
Seriously, how do you want to connect a standard-res game-pcb to a VGA-screen? You will need a converter. Or put in a PC with a 15kHz compatible gfx card and use soft15kHz or emucrtdrv.