I'm sorry but it said "Apple could not verify “dressmaker” is free of malware that may harm your Mac or compromise your privacy." When I tried to open it. I have download the OSX version
Oh right, I see what you mean. If you go to system settings and click on "security" and then scroll down there should be a little popup of the app and an ability to click "allow" application. Apple sometimes blocks things. Hope you find it :