Just tested it and it's working fine on my Mac. Can you describe your problem a little more?
When I download the MacOS zipfile and unpack in try to launch the application by rightclicking and choosing open. I get the included popup.
This is because the file "Sealed Bite" in Sealed Bite.app/Contents/MacOS/ folder doesn't have the executable bit set.
-rw-rw-r--@ 1 username 841819241 37580572 Nov 29 21:30 Sealed Bite
after setting it with chmod +x it works fine.
I can confirm the issue on macos 10.15.2. After chmod +x the Sealed Bite.app/Contents/MacOS/Sealed Bite I could run it.
Extremely amazing game btw! I had lots of frustration and fun :D great ending!
Thanks also for reporting. It is weird as I'm am able to run it without having to change the permissions on my mac. Nevertheless, I am still using Mojave 10.14.6, which may explain the issue.