Ok the first way is to use mugen 1.1 with MugenHook by ermannaccer and a custom frontend for playing the loop (I suggest using multimedia fusion in principal or the way with Game Maker Studio) and use the next loop

First make a mugen system def with all modes desactivated, this will give you the bucle or loop of intro and demos

then make a mugen system def with only arcade mode name in system def

when you have your two system def modificated with two names, we can begin with the frontend desing



Step 1: be sure that in mugen.cfg you only have full screen mode, this is a trick for mimicking a classic arcade operator

Step 3: make a shortcuf file of your principal mugen file, example: mugen.exe , but remember, make a shortcut file

4.-go inside the propierties of your shortcut and in the shortcut browser look for tag or destiny line "where is specificated the location" and in the first location line add quotes and add the command: -r,, specifically -r <sysfile> , so you will make 2 versions of your mugen exe with the specified system def parameter loaded

 example: C:\Users\AUSERPC\Downloads\No_limit_Winmugen_patch \No_limit_Winmugen_patch\Winmugen.exe -r  <systemattractmode.def>
example: C:\Users\AUSERPC\Downloads\No_limit_Winmugen_patch \No_limit_Winmugen_patch\Winmugen.exe -r  <systemonlyarcademode.def>


Step 4: in your frontend put a button that simulate escape button, so the idea is that the bucle/loop of intro and demo fight still excecuting until push button, so the first mugen will close and open the another mugen with arcade mode (to this point is very important that you have the mogenhook latest version cuz that can make that your second player joins during the match)

Step 5: so if anything goes right, after closing the mugen with attract mode the only arcade mugen mode (I really really recommend you replace in your system.def file the arcade mode name to press start or push p1 or p2 button like classic arcades)