mrkgnao: These are alternative downloaders for GOG games (the first was developed by GOG, the other two developed by users). I don't use any of them. I just download via my browser. I also don't use Galaxy.
CuCuJambo: Thank you for your honest answer, i thought will be more fast to open GOG from shortcut and i do not need to open browser, but let me see whether my thoughts are right.
3) Downloading with your browser - this isn't very recommended, as it offers no pausing/resuming, and no error protection???
You can download GOG games from a browser but with using external downloaders. I assume you are on Windows, and as such, you have Free Download Manager. Download your GOG games with it if you want a really powerful tool at downloading.
And GOG Galaxy is just meant to be a gaming client for GOG's side, something a lot like Steam and Origin, except its selling point is that you decide whether you want it or not when playing games downloaded from GOG, not use it according to CD Projekt's will. At this stage its just a beta so things don't really work out well, but what GOG Galaxy does that's good right now is the popup chat window, downloading game backups or downloading and installing straight away without the backups, and having library management in the client, with online showing all your library and offline just showing what you downloaded. Also if a game updates and breaks something, if you set the update procedure to manual, you will be able to rollback to the previous version of the game. It will soon include features that you can disable (you decide you don't want achievements for example), and that's what I remember off the top of my head.
Just remember that if your experience with Galaxy is poor, such as when browsing te forums using it, remember that its still in a 'beta phase'. There is a pinned thread that caters to GOG Galaxy development and squishing of bugs, etc, and there is an entire wishlist spot for whatever features its missing if you wish to see it improve.