
You can find out more about the Stream Play Beta, the full list of supported games, and how Proton works in the Steam post. They have mentioned that there could be a performance difference for games where graphics API translation is required, but there is no fundamental reason for a Vulkan title to run any slower.
WINE FOR MAC PLAYING WINDOWS STEAM INSTALL
You can now install and run Windows games with no Linux version currently available, directly from the Linux Steam client, complete with native Steamworks and OpenVR support.

Whether you have purchased your Steam Play enabled game on a Mac, Windows, or Linux, you will be able to play on the other platform free of charge. Using Steam Play the gamers can purchase the games once and play anywhere. The list of games that they are enabling with this Beta release include: Beat Saber, Bejeweled 2 Deluxe, Doki Doki Literature Club!, DOOM, Fallout Shelter, FATE, FINAL FANTASY VI, and many more.


In order to identify games that currently work great in this compatibility environment and solve the issues, if any, they are testing the entire Steam catalog. The included improvements to Wine have been designed and funded by Valve, in a joint development effort with CodeWeavers. Proton is an open source tool, allowing advanced users to alter the code to make their own local builds. It uses Proton, a modified distribution of Wine, to allow games which are exclusive to Windows to run on Linux and macOS operating systems. To provide compatibility with a wide range of Windows-only games to all Linux users, a Beta version of the new and improved Steam Play is now available.
