Unfortunately, Apple makes it very difficult to release cross platform software with their new OS. I would need a developer account, and I need a Mac to build the game and prepare installation packages.
There's a solution though! The source code is available for free, and it includes build instructions: https://github.com/jobtalle/koi
Alternatively, you can run it as if it were a website, since the game was built using HTML, Javascript and WebGL.
Multiple Mac users have already built the game for themselves from source, and it runs great on Mac!