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It has to be the folder "inside" the .app file. See, each .app file in MacOS has a "content folder" inside it. Maybe you're in the wrong directory. You have to right-click the .app file after the .zip file was extracted and select "show package contents". Then, inside this folder, open a terminal inside its Contents/MacOS folder. To confirm you're inside the right .app folder, use the command "pwd". You should get something like:

/Users/<username>/Downloads/Siren Head.app/Contents/MacOS.

If you're somewhere else, it should not work.

That's what I  did. It was on the MacOS folder inside the package contents of the application.