Any clues? Can't get past the startup videos, both games just sit here forever.

Also, what's in these Enhanced versions? Couldn't find anything talking about them. I've always played the originals through gzdoom without issues.

Try updating/re-installing your Visual C++ Redistributables, I remember another player ran into a similar problem with the enhanced versions not working.

Here it freezes at the same spot, but eventually proceeds after ~1min.
(I'd guess that it's calling the Bethesda mothership and it's a blocking network i/o?)

Fun fact: if I don't close Steam, it freezes at the start of the first video! And Steam thinks I've launched the game from it, heh (Looks like the games are loading steam_api64.dll and reporting in)

Pressing space should pass the movies. But it is prety inconsistent.

I suspect It is the Unity movie player. It use to act strangely and laggy in every game it is used.

That lag with movie happen with all Bethesda games, not just this

Sounds like it's just a slightly tweaked or cracked version of the steam release just like the GOG version of Doom 64.

I've given up. I was mostly checking this for the local split-screen multiplayer (which is indeed cool) and to give a chance to the WAD downloader, but this thing just doesn't work correctly.

They have a proven codebase in their hands that has been ported to every imaginable hardware on earth and this is what we get:
-Have to close Steam, otherwise it will freeze more and will think it was launched from it
-Hope that it doesn't freeze completely during the intro videos
-Try to download some WADs without it freezing, like in the attached screenshot (Bonus: I didn't find a way to scroll the WAD descriptions, does it need a controller?)
-In the end it will freeze on exit 100% of times?

(VC++ redists are up to date here)

If the issue is with the Enhanced versions trying to communicate through Steam and for some reason failing in your case, try and rename/delete the steam_api64.dll file from the game's Plugins folder (<Doom I or II Enhanced>\<game name folder>\Plugins\x86_64\), it should stop the GOG version from trying to connecting to Steam. I tested this out with the current GOG build while Steam was running and renaming the file prevented the game from appearing in my Steam activities. The WAD descriptions can be scrolled by hovering your mouse over to the description window and using the mouse wheel or using the mouse to move the scroll, but other than than there's no way to scroll the description with just keyboard alone. It's certainly not a cracked version of the Steam release. The GOG version of Doom Enhanced has some newer DLL files in the plugins folder and a few different files than the former does.

Reinstalled just to test if removing the steam api dll fixes any of the crashes, but no joy.

About scrolling the WAD descriptions with the mouse wheel: the scroll bar goes back up immediately here.

Sounds more like a problem with your PC than the game itself. My computer is over 9 years out of date in terms of specs and I'm not experiencing crashes with the base game and official addons or problems with the menus.

Well, if it didn't work at all for everyone it wouldn't be launched, right? (Hopefully, but we know sometimes it happens haha)

It's a run-of-the-mill Unity Engine shell over the regular game, I can't imagine what could go so wrong and I don't care enough to debug. I've played a few hundred Unity Engine games with my workstation. I'm trying to avoid sounding like a know-it-all but I know what I'm doing.

Will try again in a few years when the urge to replay these classics appears again. Thanks for your suggestions.

Asked around, looks like most failures are on AMD hardware.

I didn't have this issue before but after re-installing my game after testing a thing I testing on it, now the scroll bar doesn't even more in the WAD descriptions.