For anyone who wants to play this game (and Requiem of the Abyss) on mac, you can do so by launching it through Ren'py!
In order to do that you'll need to download version 6.x (NOT 7.x or 8.x) of renpy, and then simply drag the unarchived game folder into the renpy folder, run renpy and you'll see it in the projects where you can launch the game! :)