Highway for Mac seems to be a damaged file
Viewing post in Highway Encounter 3D comments
Have you tried the instructions in the readme for running on a Mac? Here's some extra help I've been given:
Since the app is not signed for a Mac, it shows "Application from unidentified developer" or even "Application is damaged and cannot Be opened" on first start. Try to open you game with Ctrl+Right Click and then Open. If it's not helping, open Terminal, enter "sudo xattr -cr /Path/To/game.app" and then open your game. More details here: https://support.apple.com/en-gb/guide/mac-help/mh40616/mac and here: https://appletoolbox.com/app-is-damaged-cannot-be-opened-mac/