Morse Runner is a Windows-based contest simulator developed by Alex Shovkoplyas, VE3NEA. Using Wineskin, it has been successfully and seamlessly run under OSX, and made available here for download. Sure, you could use Wineskin to do this yourself (and save me some bandwidth), or you can pull the ready-made dmg from here.
Running Catalina? Go to 'Download' to read the latest (and grab a box of tissues)

: These repacks are "lossless," meaning no textures, audio, or cutscenes are removed or downgraded to achieve the smaller size.
A FitGirl Repack is a highly compressed version of a game's installation files. In the case of Shadow of Chernobyl , the repack takes the original game assets and uses advanced compression algorithms to shrink the download size significantly—often by 50% or more—without removing any actual game content. Stalker - Shadow Of Chernobyl Fitgirl Repack
S.T.A.L.K.E.R.: Shadow of Chernobyl remains a cornerstone of the atmospheric FPS genre, and for those with limited bandwidth or storage space, the of this classic is a popular choice. This article provides a comprehensive overview of what to expect from the repack, how it differs from the original, and critical safety tips for players heading into the Zone. : These repacks are "lossless," meaning no textures,
: Often, users can choose to skip downloading non-essential files, such as voiceover languages they don't need (e.g., Russian, French, or German), further reducing the initial file size. Key Features and Content Key Features and Content
Confirmed working on: El Capitan, Mavericks, Sierra, High Sierra, & Mojave
MANY reports that it DOES NOT work on Catalina. It is very unlikely that it will work under Catalina in the near future, as it would require some pretty hefty development on Wine (they're working on it). The only other option I see is for some nice macOS developer to take the original code (it's open source!) and re-write it to run natively on 64bit macOS (go ask any developer, this is a lot of work). Since Xcode is now free if you're running Catalina, I'm happy to give it a try... when I can afford to buy a system that can run Catalina :)
If you have questions or comments about using this application under OSX, please email them to ki4stu k4iz at arrl dot net.