You have two choices. Either you download some sort of Windows emulator, like Wine, and run the game from there [it works, but I generally find that animations, even running around on a map, get too choppy to make it an enjoyable experience, though others seem fine with it -- it may depend on the quality/newness of your Mac, on its speed and memory, etc.]. Or, you can slightly modify this game [because it's an RPG Maker MV game] to make it run natively on a Mac.
Here's the procedure, nothing too hard:
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1. Take this RPGM MV
mac game base:
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taken from another RPGM MV mac version of a game.
2. From the Window's RPGM MV version of the game you downloaded, there is a folder called 'www'.
3. Right click the
game base, Show Package Contents, browse to Contents > Resources.
4. Move the 'www' folder into the 'Resources' folder inside of RPGM MV mac
game base. Rename it to 'app.nw', and move package.json into 'app.nw'.
5. Open package.json in a text editor and edit these lines:
"main": "www/index.html", to "main": "index.html",
"icon": "www/icon/icon.png" to "icon": "icon/icon.png"
6. And you're done! Rename the app to whatever you want, for example 'Coceter Chronicies v.12b.app'.