At a glance
GRIS has a Mac version: Steam sells it for macOS. The Mac requirements list only Intel: on Apple Silicon Rosetta 2 runs it, and old Mac versions sometimes do not start on current macOS. Try it in Steam for Mac first.
GRIS came out on Steam on 13 December 2018, made by Nomada Studio.
What your Mac needs
The Mac requirements list only Intel.
Minimum macOS in the Steam requirements: 10.11.
Steam requirements list at least 8 GB of memory for GRIS.
Allow about 4 GB of disk space for the Mac version.
How to play
Open Steam for Mac and install GRIS as usual.
If the Mac version will not start, you can install the Windows version through Uncork: download Uncork, sign in to Steam and install GRIS from there (4 GB). We have not tested it ourselves.
The Windows version through Uncork needs a Mac with Apple Silicon (M1 or newer).