So I got it figured out and the game does work now. I'm afraid the instructions you were given are incorrect, though. Here's what I did. Download both the Mac version of the game and the zip file you linked on Google Drive. When you open both you'll have two apps, both named "Game.app". View Package contents on both apps in separate windows, then navigate to the /Contents/Resources/app.nw/ in both. The Game.app from Google Drive will have nothing in this folder, while the Game.app from the Mac game package will have all the game contents. Copy the entire contents of the Mac Game.app over to the Google Drive Game.app and close both windows. Then replace the Game.app file in the Mac game folder with the newly updated one from Google Drive. It should now launch properly. Note, that the Game.app file must be moved into the folder where the original Game. app file was or it will not launch. If you'd like, I can take screenshots of the process and send them to you.
I'm glad you got it to work for you!
Feel free to add screenshots to your post for posterity if you think it'd be helpful. It's hard to put an official guide together when all the solutions I have are only confirmed to work for one or two people, but it'll be good to have your steps around to see if they work for others.
Speaking of others - if you happen to be reading this comment chain trying to figure out how to get the Mac version working and this method works for you, drop mephits an upvote. It's the easiest way to let me know the method worked for you as well.