Welcome, Mystik.
First of all, please note that the game card (site page) for each of those games indicates they are for Windows only.
Grargar has provided the necessary workarounds. You could also use Parallels, of course.
Myself, I do everything on a Mac + game on my Mac when possible, and have some offline windows computers for my Windows-only GOG games.
There are a bunch of games compatible with Mac here on GOG just directly from the download. You can sort by system on the "Games" tab, such as
here. Do make sure you check system requirements. I have stayed on 10.7 and there are some newer games that require a higher version of the OS. A few games also are not compatible with 10.11.
Enjoy! :)