If you download the mac renpy launcher from this page:
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you can use it to play the PC version of the game (and the PC version of most renpy games). You just place the folder containing the game in the renpy launcher folder, open the renpy launcher app, and then select the game from the list that appears. There's also a thread on the forum that provides more detailed instructions if needed:
In my experience, you don't usually need to do what the thread above suggests (eg make a new folder) but can can just unzip the PC version you've downloaded and put it in straight in the renpy app folder. Very occasionally it doesn't work for one reason or another, but I'd say it works with 95% of the pc versions I try to play on mac.