Hi,
I just get windows 98 to run on my emulation machine via retroarch and I could get some of my GoG library to run on it if there was the option to donwload the game's ISO and not just the executable ?
Thanks.

Use an ISO creator program to make an ISO of a classic style data CD, putting the GOG installer files into the data CD ISO, so you can then open the ISO in your Win 98 emu, and copy the files from the ISO to your emu for install.

edit: fix typo

I'm not sure the installer would run on Windows 98, or versions older than listed on the store page for the game. If OP posted the game it would help give more specific tips. You might have to run the installer on a newer system, find the game files (and any registry settings, especially if it's not a DOS game), and create a custom ISO (or other virtual disk) based on those files.

For the DOS game case, the GOG installers would set up something like DOSBox to allow it to run on systems newer than XP. That probably isn't something you'd want to run on Windows 98, since it can just run DOS software directly.

Maybe there are other ideas in threads such as this: Windows XP retro gaming machine and GOG

Gross, Retroarch? Of all the emulators with a bullying and toxic creator; and multiple counts of stolen or unlicensed code and blood on their hands?

Why not just PCEm or 86box?

I used DOSbox-X for doing my Win98 with 98lite install in an emulator.
The install was very straight forwards, and helped by the fact that I still had all my old Win98 installs, including Windows Update patches.

The older Gog games are optimised to run on modern hardware. The intent is not to make available older games to be able to run authentically on their original hardware (emulated or real). I don't think any of the games available here would run easily on Windows 98.

It all depends on the games you want and what you're trying to do. GOG uses InnoSetup to create their installers and compatibility for that is listed as "Support for every Windows release since 2006", ie, Vista. If those installers fail under W98, games might still work if you extract the game files with InnoExtract. Running DOS games natively under W98 (without DOSBox) should work though you'd need to configure all the DOS, SoundBlaster, etc, settings yourself "old school". If you want DOS games that need a CD-ROM "live" to play (eg, 90's FMV games), you may need an actual CD-ROM drive and burn the files to disc as you'd miss DOSBox's IMGMOUNT trick in mounting a file as a fake drive, which is how GOG's DOS games are pre-setup.

If you want 32-bit Windows games too, "native" Windows 98 compatibility means no 64-bit games, no DirectX newer than v9, many dependencies (VCRedists) from the 2000's won't work, having to emulate an old GPU + setup the drivers for it, etc. If all you want is DOS games though, it's a lot easier to setup DOSBox / ScummVM "natively" and emulate just the game rather than to emulate a whole W95-98 OS and run games "natively" under that.

I Didn't knew about it, i'm just a gamer woho use the more common and accessible software but i'll search for your proposition if it not too difficult to use instead thanks.

@AB2012 : Well that for windows games that dont run on dosbox, like Diablo 2 or Heroes of Might and Magic 3, i wonder if they would run with ISOs on an emulated win98

I still have some old CD but lost somes of the keys, would be great to if in the game's download section we could get a new installing key for old school systems ?

It may be possible. GOG don't sell Diablo 2, but I can confirm the original disc version of that (and Lord of Destruction) still works even under Windows 7-11. You need to install "DirectPlay" first and possibly add dgVoodoo, but if it comes to it, it's still playable (in widescreen with a patch) even without any emulation / source-ports.