Hmm, it's giving me the same error message still... Sorry I don't mean to be a hassle! Just excited to play your game.
No worries! We'll figure this out together. The problem might be that I used a tool to upload the dmg which automatically compressed it as a zip. This time I uploaded the dmg file directly. Please try downloading it again and if it still doesn't work, maybe you could refer to this page for possible solutions: https://osxdaily.com/2019/02/13/fix-app-damaged-cant-be-opened-trash-error-mac/.
Let me know how it goes. Thank you for your patience! :)