When I try and open it on OSX (10.15) I get an error:
"The app has been modified or damaged"
On Mac, you need third-party permissions to run the game. Please, read the install instructions, there's a link with info.
Thanks - I'm used to doing that and I'm familiar with the message and how to work around it, but this seems to be something different: it says the app is damaged and it's not possible to 'unlock' it from the security menu.
OSX 10.15 no longer has the "anywhere" option, apps need to be signed now by a developer certificate :/ a quick fix is to run the following command in terminal: xattr -r -d com.apple.quarantine <path to file or app>