Mugen-Pi-4

V3.5 Released

If you don't know select mugem with all updates .

Go get a coffee/cigarette/drink this will take some time
If successful it will return to retropie with a new wine category, with default mugen inside of it .
Go to wine/wine-apps then launch wine tricks.
Let Wine update and install gecko and mono. It will prompt you .
Exit wine tricks from menu then
Open wine config in retropie menu to use "optimize before playing" below.

Switch wine version to xp .
Go to graphics, then turn off decorate window. NOT NECESSARY HELPS VERY FEW GAMES THAT DONT LAUNCH FROM RETROPIE. CAUSES NO HARM IF OFF THOUGH.
Close Wine Config. You will be taken back to retropie .

This installer installs wine and box86 .
This installer can used to play a bunch of old windows games.
Optimization of Wine emu is possible will add a better performance area soon .
Included files in this github with lyt extensions are qjoypad layouts . Configured with a ps3 style controller . Will update every now and then .

Open pixel desktop
Move mugens to home/pi/retropie/roms/wine/games
Optimize your data/mugen.cfg if necessary .
Rename your exe to mugen.exe .
Return to Retropie then restart emulation station .
If successful your game should be under wine/games/mugenfoldername/ in retropie.
Want video instructions ? Here ya go .

Open pixel desktop
Go to menu/games . Then click qjoypad .
Click on qjoypad icon in system tray .
Click add layout .
Name layout same as exe name . Example want mugen controls name mugen then name mugen exes mugen.exe. THIS IS CASE SENSITIVE.
Click quick set .
Press button want to map then button your mapping to. Example want a button to be left click, press a then left click.
Repeat this for all buttons you want mapped .
When finished click save .
Go back to retropie. Restart es and load game .

*Direct exe launch

Have a keyboard plugged in
Open pixel. (in retropie press f4 then type startx hit enter)
Find and rename your mugens.exe exe to mugen.exe.
Exit desktop and return to retropie . ( start/quit/exit-to-command-line then type emulationstation hit enter)
With keyboard attached open mugen in retropie .
Go to Options
Turn Joysticks OFF for both players .
Go to input config for player 1.
Configure buttons with controller. Repeat for player 2.
Go back to options and save your configuration.
*If you dont like the controls still follow steps below
Open pixel. (in retropie press f4 then type startx hit enter)
Click start/games/qjoypad . Then double click qjoy icon(little blue controller) in tray .
Select mugen layout in qjoypad. Click clear, then click quick set .
Press the button you want to be escape then press escape.
Repeat for all buttons youll use it mugen.
Repeat this for player 2. Then click update.

See Mugen Compability List Here

See Wine Compability List Here

Make sure to change all the mugens you add controls in and mugen.cfg file or in game.
If your exe name is not mugen.exe . Qjoyoad will not load mugen layout to map your. ontroller to keyboard buttons.

Credit for link to pigamer

A bunch heres a list on retropie forum. Different method same results, emus etc.

This is community made and maintained . Hopefully soon RetroPie/Raspberry Pi will use wine/box86. George McMullen has a pull request in Retropie github.
With V3 major props to Supreme Retro Gaming . They worked hard and made it so much better.