I'm unable to launch this game on Catalina - any advice? I just get an unhelpful dialog that says "The_Haunted_Island can't be opened."

I have the same problem! any solutions?

also having this trouble, pls, i just wish to play the game

Same problem!

try opening terminal, and entering the following immediately after unzipping the file in the downloads folder: 

cd ~/Downloads/The_Haunted_Island_mac

chmod -R +x The_Haunted_Island.app/Contents/MacOS

(worked for me!)