extract the app in your Applications directory, then paste this in terminal "cd /Applications/Pixel_Character_Creator.app/Contents/MacOS" and press Enter , it should change your directory to /Applications/Pixel_Character_Creator.app/Contents/MacOS , if true then paste this in terminal "chmod -R +x" this will change permission for the folder to Read/Write/Execute, then paste this "sudo spctl --master-disable" and try to double click the app again . if it doesn't work then paste this "chmod 755 /Applications/Pixel_Character_Creator.app/Contents/MacOS/Pixel_Character_Creator" and try to run the app again , it should work now and you should enable your master again by pasting this command "sudo spctl --master-enable" , please reply to this comment if the problem was solved , thank you :)