Huh ? Do people really have such a problem with this ? First , go to openemu . org , then click the arrow next to download now and choose OpenEmu Experimental , download that . Then when you have OpenEmu , open it up , go to preferences and choose the cores tab , look for MAME and make sure it is installed . Then go to the library tab and make sure Arcade is ticked in the available libraries . Then , simply drag a MAME rom . zip file don ' t extract it into OpenEmu and you should be good to go ! That ' s the basics , if you have problems with certain games look at yuenadan ' s post . He mentions BIOS files and dependent roms . For example , to play Metal Slug mslug . zip you will need neogeo . zip also . You can simply drag them both into OpenEmu and then I think you can delete the neogeo rom , but when the prompt comes up saying do you want to keep the file say yes to ensure you still have the BIOS file needed . Games since around 2000 such as Marvel Vs Capcom 2 do not run unfortunately and you will have to wait for a newer version for support for these . Probably around the same time we get support for consoles such as Playstation 2 so I wouldn ' t hold out