Mortal Kombat won't work on the newer versions MAME. you have to get an older version around .76 or something to get it to work right. Google CoinOPS on MAME for the best version of MAME on XBox. Mortal Kombat and NBA Jam and NARC and other games like that will play perfect on it, but without sound. Tons of fixes on it thought that make it the most perfected XBox version of MAME to date.