I saw a bunch of complaints about that. If someone already posted a fix, please disregard this post (and hopefully link the original) but if not, here's a temporary solution. Just paste this into your browser's console:

const a = document.querySelector('.layout .ng-scope');
a.firstChild.innerHTML = '';
a.classList.remove('productcard-player');
a.style.height = '250px';

Either way I'm sure GOG is working on a fix, so this won't be necessary for very long.

How "temporary" is it? Edit: I mean, I'm curious for how long will the browser remember it.

Umm... well, as temporary as you want it to be. I mean, if you like it, you can use it for so long as you want to. Although once GOG addresses this complaint there will no longer be a need for it.

I guess, I am not sure what you are asking.

Edit: Oh, I just saw your edit. Sorry.

Yea, the browser won't remember it. What I meant was, you can paste in into the console to test it and see if you like the result. If you want it to be permanent, you'll need to add it to your user scripts. Then it'll run every time you are visiting gog.com.

I see, thanks for the answer.
E: (yeah, I edit my posts a lot. ;p ) I've put together a little css thingy to achieve more or less the same, but it requires a browser extension...

Heh. Well, I already have a published extension for GOG, so I could simply add this functionality there, but I have a reason to suspect it would cause another fecal storm on the forum...

I guess only if enough people want it.