There are two ways that will probably help you:
Easy way:
The game is available for free on Steam as well, there you should have no issues installing and playing the game on any platform.
Technical way:
You can try the following: open the terminal and navigate to the downloaded game. Then type: "chmod +x Drova.app/Contents/MacOS/Drova" this allows the app to be recognized as an executable. And then this command: "xattr -r -d com.apple.quarantine Drova.app/". This allows the run to be run after downloading and unzipping it from the internet.