'Play for free' it says on the button which would otherwise just have said 'add to cart'. What's the difference? Is GWENT multiplayer only? Is it standalone, or does it require The Witcher 3 to play? Do I have to be online to play it, even in the case of it having single-player features? Galaxy-dependant?

I would appreciate your advice.

Too slow I was.

Online only free to play multi-player with micro-transactions. There is an offline single player game too but I forgot its name. No other Witcher game is needed but Galaxy IS needed.

Yes, as the others have said it is Galaxy-dependent, which means it has online DRM. It is multiplayer only and is based on a pay-to-win micro-transactions business-model. And no, that is no joke. GOG has really sunken that low with the release of GWENT. Also this version of Gwent was heavily altered from the one in The Witcher 3. Different mechanics, only two lines. After what I gathered it is closer to Hearthstone than to the original Gwent.

My personal advice would be: stay away from it.

Thank you for your answers guys. It was pretty much what I thought it was, which is why I hesitated to push that button. I also know about Thronebreaker, but what I really would have liked, is a solitaire like game with just decks of cards doing things. Think about it, CDPR. To sit down with a couple of rounds of intricately animated card puzzles or combat. Nice, casual and addictive.