Alright... OK, first things first, try this:
1. Open 'System Preferences'
2. Go to 'Security and Privacy'
3. Go to the 'General' tab, then at the bottom (above the lock), grant an exception for the 'GROVE' app and click 'Open Anyway'.
If that doesn't work... try this:
Download the normal version of NW.js (https://nwjs.io/) and transfer the app to Applications. Make sure to grant it permissions under the Privacy and Security setting after trying to open it.
In terminal, launch the game with this command (substitute NAME for your Mac username): open -n -a nwjs --args "/Users/NAME/Desktop/Grove_0.308"