Some advanced versions (like the "Groove" hack) allow players to choose between '99 and '98 fighting styles, effectively bringing back the more traditional movement and meter management from KOF '98 while keeping the '99 roster.
Players can spend three power stocks to enter Counter Mode (infinite super moves and special canceling) or Armor Mode (taking hits without flinching but sacrificing the ability to use supers). How to Play the ROM Kof 99 Plus Rom
Playing a "Plus" ROM typically requires a Neo Geo or arcade emulator: Some advanced versions (like the "Groove" hack) allow