in the first part of our DEMUL guide, we covered prerequisites and some basic knowledge needed to get the emulator running. In the 2nd instalment we’re going to concentrate on the meat and bones, the emulator itself. DEMUL is easy, if you know whats exactly needed, something that isn’t really explained in detail anywhere. By the end of this guide you’ll be playing Marvel vs Capcom 2 in no time.

I’d highly recommend you read part 1 of the guide so you have a good understanding of how DEMUL works, what exactly is needed and a few other bits and pieces. This guide also assumes you have access to full MAME ROM sets, something I can’t tell you where to get

Before we start configuring DEMUL, we need to prepare our ROMs directory.

Preparing our ROMs directory

As mentioned before you should have 3 sets of MAME files. They are:

  • MAME 0.205 ROMs (bios-devices)
  • MAME 0.205 CHDs (merged)
  • MAME 0.205 ROMs (non-merged)

I’m going to use my I:\DEMUL\TEMP as a temporary staging area to prepare the ROMs. Essentially, you’re going to be taking the contents of the 3 MAME ROM sets you downloaded and combine them into one folder. This is so DEMUL has access to everything in one directory and it makes it easy to configure MAME as well (if you’re going to use it).

  • Navigate to the folder that contains all your MAME CHD 0.205 folders.
  • Select all files (CTRL+A).
  • Right click > Cut.
  • Browse to I:\DEMUL\TEMP.
  • Right click > Paste.
  • Repeat this process another two times, one for the main MAME ROMs and another for the BIOs files.

Our I:\DEMUL\TEMP folder should now consist of all the ROM, CHD, and BIOs files from the 3 MAME sets.

Separating DEMUL ROMs

From here you can head down two paths, you can either:

  • Leave all your ROMs like this, and move it to your MAME directory.
    • You can use this directory for MAME, and then just point DEMUL to this location as well.
  • Move all the DEMUL ROMs out of here to a separate folder.
    • This is if you want to separate DEMUL roms or you want to delete the rest of the files to save space.

If you want to split up your MAME and DEMUL ROMs, I’ve developed a .BAT script to copy all the files needed solely for DEMUL. Put this file in your new ROM directory and run it. It will make a copy of all the related DEMUL files and folders (.zips and .chds) into a sub-directory which you can then move off to where ever you want.

For the sake of this guide I’m not going to separate it out. I will now rename the TEMP folder to ROMS. So if you’ve been following along you should now have I:\DEMUL\ROMS.  Whichever way you chose, our main ROM directory for DEMUL is good to go, we can now move onto the emulator.

DEMUL Configutation

Go ahead and download DEMUL from the official website. At the time of writing the latest version is 0.7 Build 111117.

  • Extract the contents to I:\DEMUL\.
  • Run DEMUL.exe.
  • The message “BIOS and Paths not configured” will appear.
  • Hit OK.
  • You’ll now be at the configuration screen.

It should then automatically set up your paths. If it doesn’t do this automatically, see the screenshot for what I’ve setup.

There are a few things to note in this section:

  • Video plugin – All the plugins leave as is per the screenshot, but ensure that the Video Plugin is gpuDX11.
  • Rom and BIOS path – Add the path to your folder that you setup previously which contains all the ROMs, BIOS and CHD files.

That should be in for the plugin setup, once you’re done here hit OK.

If for some reason the video plugin field is empty and you can’t select anything, don’t fret. DEMUL requires some specific Visual C++ redistributables and DirectX Runtimes to be installed for this be visible. I had to find this out by trial and error through many installations. Install all of these, and re-run DEMUL, you should be good to go.
  • Microsoft Visual C++ 2010 Redistributable Package (x86) / download
  • Microsoft Visual C++ 2010 Redistributable Package (x64) / download
  • DirectX End-User Runtime Web Installer / download

Video plugin configuration

We are now going to move onto video configuration. These settings may vary from setup to setup so I can’t promise they’ll work for everyone. I’ve found that below ones work well for me on a decent PC for smooth 60 gameplay.

Go back to the main screen of DEMUL. In the top menu select Config > Video. Set your options as per below

  • Window Resolution – 640 x 480
  • Vsync – Enabled
  • Start in Full Screen – Enabled
  • Aspect Ratio – 4:3
  • Linear filter – Enabled, 8 layers.
  • Naomi2 Thread – Enabled
  • Disable Opaque Modifier – Enabled
  • Disable Translucent Modifier – Enabled
  • CV1K Blitter Limit – 70000000

Sound plugin configuration

On sound configuration there isn’t much to do here. One thing that I’ve noticed is that the sound buffer size will need to change depending on your PC so I can’t promise what here will work. If your sound is laggy but your gameplay / video is smooth, experiment with changing the buffer size settings until it becomes normal.

From the main DEMUL screen go to Config > Sound.

  • Sound Disable DSP – Enabled.
  • Buffer Size – 4096.

Joystick plugin configuration

The final thing we need to setup is of course our controls. In the main DEMUL screen go to Config > Controls.  For any NAOMI or Atomiswave games, you need to setup Joy 1 and Joy 2 (NOT Dreamcast). When you go into each joystick configuration, be sure to set Digital for your main directional inputs and not Analog. Once that’s completed hit OK.

I’ve included below screenshots of all the settings from the various plugin configurations.

Now all that’s left is try and run a game. Back at the main DEMUL screen go to Load > NAOMI / NAOMI2.

Pick a game and if you’ve followed along correctly, then success! You’ll be treated with the NAOMI bootscreen and that should be it.

Command Line Configuration

If you’re using Big Blue or some other front-end that requires the command line inputs to run DEMUL games, I’ve put them below in case anyone needs them. NAOMI and Atomiswave games launch slighty differently but the command is pretty much identical.

demul.exe -run=naomi -rom={0}

demul.exe -run=awave -rom={0}

{0} is a placeholder for your ROM name. To get the correct ROM name, in DEMUL hit File > Load NAOMI or Atomiswave. In the column that says Name, that’s what needs to in place of {0}. Also do not put the full path to the ROM file, just put the ROM file name.

Full screen settings

If you plan to launch DEMUL from a front-end, then there’s a few other settings that we need to configure to ensure it launches smoothly. The below shows how to disable the menu bar at the top when DEMUL launches. Usually you’d press F3 to hide it but this gets rid of this automatically.

  • Browse to your DEMUL.exe.
  • Right click > Properties.
  • Go to the Compatibility tab.
  • Under settings, enabled Disable fullscreen optimizations. 
  • Hit OK.

DEMUL functions a bit weird when it comes to this particular setting. You must go into the GUI, at least once, and launch a game after you define the full optimisation option for it to work via command line. Basically if you just try and launch DEMUL from command-line after enabling this, it won’t work. Go into the GUI and launch a game. Then try again via command line, it should launch with no menu bar.

Closing words

I mainly wrote this guide due to the lack of DEMUL setup instructions out there. Yes there are plenty of YouTube tutorials and what not but none of them really explain what the ROM requirements or even the Visual C++ installations needed which mind you, drove me absolutely insane. Hopefully this guide will make your DEMUL setup experience fairly painless and you’ll be playing Marvel vs Capcom 2 in no time.



Chad is someone who wishes arcades were still around. This also happens to be his site where he rambles on and on about games and emulation. He can also cook a mean cheese toastie.


  • Dave Fumarola says:

    Thanks for the in depth walk through. It really helped out. I am getting some weird white dots on the screen while I’m running games. Any ideas what it can be?

    Thanks again

    • C D C R U Z E says:

      Could you post a screenshot / photo of the error and I’ll try my best to help you out.

    • EvilT says:

      I’m not sure if you have resolved this but you have to make sure that you used the DX11 plugin, NOT the DX11old plugin.

  • Things Geek says:

    Have you ever found a way to get rid of the cursor when demul loads? Without having a need for a mouse to move it away?

    • C D C R U Z E says:

      I’ve always just relied on the frontend to hide my cursor. I use BigBlue (documented here on the site) and it will auto hide the cursor as soon as it starts. Not sure which frontend you use but yeah I’d start there and see if there’s any similar options.

      Alternative is find a way to change your mouse schemes in Windows via batch file. Find an invisible mouse cursor set and run the batch file as a part of when Demul launches or when your frontend launches. (or just leave it permanently invisible)

  • Scott G. says:

    Thanks for the guide, however I have a different problem, When trying to load naomi games, the emu always complains something is missing. is there a way to verify games?this is getting very frustrating.

  • Scott G. says:

    hello, i am asking for help again because i have tried and cannot find good bios for either naomi or sammy systems. Without the use of torrents, where should i look? have usenet access however am at a loss.
    Thank you
    Scott G.

  • Kevin Kovacs says:

    I read this guide thoroughly and I can’t get this emulator to work either. I keep getting an error saying unable to find the bios in the romset but it is there for sure and spelled exactly as it supposed to.

  • Amilcar says:

    Hi, thanks for all the info on DEmul.
    I’m using GameEx as a frontend for all my emulators so it need line commands. One of the most frustrating is Naomi_gd roms.
    On normal straight forward Naomi roms alls ok. But when I use the line command supplied its always short of the chd rom even though they exist .
    is there a paticular folder or some folder structure that the CHD roms can load as zipped files.

    Thank you

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C D C R U Z E is ..

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