So Hellfire from CD works fine with GOG's version. Heres how to do it. I did this under Windows 10.

For original Diablo (Non GOG scroll down.)

1) Install Diablo. (GOG's install should run fine.)

2) Install Hellfire. (HD Voices are optional.)

Make sure to not let Hellfire update via setup or register or anything.

(Setup should run if it fails to then copy the following files from the Hellfire CD to a new folder in your Diablo folder.) (Feel free to name the new folder to whatever you want.)

You will need:

hellfire.exe
hellfire.mpq
HELLFRUI.DLL
hfmonk.mpq
hfmusic.mpq
hfvoice.mpq
storm.dll

(If you have copied these files across rather than running setup.exe then skip to step 4.)

3) Go to C:\SIERRA\ and copy the entire HELLFIRE folder to your Diablo installation.

4) Download Hellfire Enchanced If you don't do this then Hellfire will ask for the Diablo CD. It shouldn't change anything else other than making Hellfire more reliable under newer systems. Extract it to Hellfire's folder and replace anything it wants to.

The game should then run from hellfire.exe.

You can then uninstall Hellfire and Sierra Utilities from Settings then Apps if on Windows 10 or Control Panel on others or 10, as uninstalling it through Sierra Utilities does nothing. If you just copied the files over then you can ignore this.

[Optional] To get Hellfire running using GOG's wrapper (as discovered by Realpsojed):

1) Run Diablo Launcher from GOG, select Video Settings and setup your graphics.

Recommended setup is:
Display mode: Same as Desktop
Presentation: Windowed - integer scaling

2) Copy the ddraw.dll, dxcfg.exe and dxcfg.ini files from Diablo\dx into your Hellfire folder (replacing the files it wants to replace.)

Next time you run hellfire.exe it should work at a higher resolution though much like GOG's version you will get black bars down the side of widescreens.

Any issues with the above feel free to ask here or PM me and i'll try to help you.

Non GOG Versions of Diablo Only!

If you own Diablo on the original CDs under modern systems heres how to get it working:

1) Install Diablo. (Setup should run fine, even under 64 bits. If it doesnt PM me and i'll try to assist you.)

Make sure to not let Diablo update via setup or register or anything.

1a) [Optional] Install the official Diablo patch 1.09. Link is here unless you already have it. We dont let setup update as it will break Hellfire.

2) Install Hellfire. (HD Voices are optional.)

Make sure to not let Hellfire update via setup or register or anything.

(Setup should run if it fails to then copy the following files from the Hellfire CD to a new folder in your Diablo folder.) (Feel free to name the new folder to whatever you want.)

You will need:

hellfire.exe
hellfire.mpq
HELLFRUI.DLL
hfmonk.mpq
hfmusic.mpq
hfvoice.mpq
storm.dll

3) Download Hellfire Enchanced If you don't do this then Hellfire needs compatibility mode for Windows XP SP2, as this mod just makes Hellfire more reliable under newer systems. Extract it to Hellfire's folder and replace anything it wants to.

Though this version Hellfire will still ask for Diablo's CD. GOG's version of Diablo doesn't need any CDs.

Hellfire should run then fine.

Any issues with the above feel free to ask here or PM me and i'll try to help you.

No idea about multiplayer i'm afraid. I only tested singleplayer. The mod says that it " activates multiplayer, gives UDP support for multiplayer." So it sounds like it.

Will Hellfire also work with the higher resolution mode or is it vanilla version only?

Vanilla only. The patch just makes the game run under newer systems.

I did try editing the ddraw_settings.ini to a higher resolution but the game still ran at 640x480 and I just lost the cursor.

Hi!
You can apply the DX graphics improvement to any Diablo. Even Hellfire. The resolution setup needs to be done before you apply it to Hellfire, the game probably automatically looks for the default installation folder. So, if you followed this guide so far:

0) Run Diablo Launcher from GOG, select Video Settings and setup your graphics. Recommended setup is
Display mode: Same as Desktop
Presentation: Windowed - integer scaling

1) Copy the ddraw.dll, dxcfg.exe and dxcfg.ini files from GOG Games\Diablo\dx into GOG Games\Diablo\ (because here's your Hellfire installed now)

Now run Hellfire.

@Pond86: you have to edit dxcfg.ini :)

That does work. Though it will make it run like the GOG version and with black borders down the sides. But thanks for that I was totally off as I thought it called the exe.

Edit: also updated the main post with your help. Thanks again.

ok!! great and thk

i got original diablo CD-Rom
i got original Hellfire CD-Rom (from Sierra software house)
i got my save (started in.. summer 1997 ^^)

but, how i solve the "32bit" problems??
i got hellfire updare 1.01
and hellfire patch for multiplayer

how i solve problems for file with 32bit?
do you know any site or forum where i can found ALL for new 64bit system?
thk

My guide was done with GOG's version with Hellfire CD and under a 64 bit.

Diablo should install from original CDs fine under 64 bit, it might not run without setting diablo.exe to compatibility mode for Windows XP SP2 though under newer systems.

Though the offical patches will not install.

If you really need the official patches I can zip them up and put them as a zip file but now that GOG's version is here and with the Enhanced Hellfire in my guide they are not needed.

Edit: Also if your running the original version of Hellfire hellfire.exe needs to be set as Windows XP SP2 in compat mode otherwise it will also display an directdraw error.

There it is, right at the top of the forum, *exactly* what I was coming here to ask.

I have had issues with Diablo running from the CD installation so, if the GOG version works and accepts Hellfire, this is good news.

Blizzard made a good game, but Sierra made it epic, so many of the best parts of the original Diablo were from Hellfire that it wold be a real shame if you weren't able to use it thanks to some obnoxious licensing hell preventing it from being sold again.

Thanks!

Also, for those who doesn't have it, Hellfire can be found in the Archive organization.

Thanks!

Just need to dig out my old disc now.

Considering that Sierra made the expansion, and Sierra after a long chain of events was bought out by Activision Blizzard, unless I'm missing something there's no legal reason they can't use the expansion.

I think the lack of rerelease of the expansion is more due to Blizzard not wanting to bring it back into canon. They've shown a reluctance to canonize expansions not developed by them directly, as seen with Starcraft Insurrection and Retribution, or Warcraft 2's 4 authorized expansions other than Beyond the Dark Portal.

Does The Hell mod work with the GOG dx wrapper? It requires its own executable, TheHell.exe, to be launched. If not, are there other wrappers for D1 that will allow integer scaled fullscreen 1280x960? (640x480 x2)

A big THANK YOU to GOG.com for bringing Diablo to modern systems! And a shout out to Pond86 for instructions on how to install the Hellfire expansion onto the GOG.com copy of Diablo.