If you are not satisfied in a month, GoG will refund your money. They will ensure that no one systematically takes advantage of this system.
With digital game stores on PC, there's an unregulated area where if you buy a game on Steam , the Epic Games Store, or GOG, you're essentially paying for the digital access service, and there are no refunds. This makes refunds difficult, but numerous laws in the digital realm are changing this. And now, GOG is taking a big step forward, making it easier to return games.
Returns without having to justify
If you want to return a game on Steam to get the money back, you have to request a refund for a maximum of 14 days and you cannot have played more than two hours. What if for various reasons you have not been able to play it or have critical errors in a point beyond those two hours?
GoG.com, the CD Projekt RED store, is known for trying to offer a good service to users. If before it always gave you games without DRM, with manuals and extras like soundtracks, now it is added the power to return games in a maximum of 30 days without having to justify anything.
For example, let's say you buy Cyberpunk 2077 from GOG and three weeks after its release you play it but find that it runs worse than you'd expect or that you're not having any fun after the first few missions. You can return it. And they won't ask you for any explanation.
However, they will be monitoring the system to ensure no one abuses it. Since the game is DRM-free, it's easy to buy, download, and request a refund after storing the copy. But like all-you-can-eat buffets, they don't expect blatant abuse of the system and anticipate that refunds will be rather infrequent. This decision puts GOG in a favorable position compared to Steam and the Epic Games Store , at least in terms of service, as they offer greater consumer security.
Source: PC Gamer
Very good GOG