Whenever I try to make an account so I can access online features, this message pops up (see screenshot)
What's going on, and why does there appear to be DRM?

I wonder, what are those "online features" which require registration?
Usless online leaderboards are understandable but is there anything more?

There are many community levels available.

You mean, one can not just install those manually like it happens with sane games? And the only method to get these levels is to register in the 3rd-party online "shop"? And pass a "license check" on top of that?

1) The devs are hosting these on their own server so everyone who bought the game can access them no matter where you bought the game.

2) I've never seen this "Ownership required" error message myself. Login with the account I created worked just fine.

And lock those free of charge community-made maps behind their DRM. Being an old doomer I fail to see this in other way than a sort of a shady behavior.

I have this problem also. I CANNOT make an account with the GOG version.

They needed to say it in advance. If they were removing online. This is B.S.

They should fix it. At least for the early comers.

We did not pay early to have limitations they did NOT disclose.

And no response from devs of course because they don't even know gog exists.

Prodeus is also missing the free MIDI album:

https://store.steampowered.com/news/app/964800/view/2981927408950619534

I just downloaded it on Steam. It's not behind a paywall or anything.

I downloaded it in gog because the developers said it was available here xD

Yeah, I'm being patient to judge the Devs though. They may have a different mindset. GOG is a different bunch of people, and there may be different coding needed to play online with people over steam etc. We do seem to watch every twitch that Devs make here.The Devs could simply be cautious.

Though I still have the same login problem as last year. There may be a reason for it yet.

i know this is late but it may be related to your password itself. i tend to use really secure passwords. At some point, my Prodeus logins started failing. i reset the password and it worked on the web and not in the game. i got curious and simplified it a little bit until was not a long string of just plain noise...

and logins started working. i am not sure if it was the very long length or if i was tripping over some collection of special characters, but it seems something about passwords in the game changed.