For macOS, if it says "this app can't be opened", right click it, select "Show Package Contents", then go to the Contents folder. Right click on the MacOS folder within the Contents folder, and select "New Terminal at Folder." Then, type this command, *including quotes:*
chmod +x "Baldi's Summer Heatwave of 98"
This will turn the app into a Unix Executable File, which allows the app to be opened. Hope this helps! **Btw this was tested working.**
Troubleshooting:
1. I can't right-click the app!
Solution: Open the Applications folder in Finder.
2. It says quote> in terminal!
Solution: Press Ctrl+C, which exits out of quote>, then put in the command again, but this time include the quotes.
3. Now it says it cannot verify that it doesn't contain malicious software!
Solution: Go to System Settings/Preferences > Privacy & Security > Scroll down a bit until you see 'Open anyway' click that.