Ok, I found out the issue: You will need to download it, then open up terminal and write unzip, then drag the application into the window eg:
unzip /Users/ProjectTetraDev/Desktop/project-tetra-osx-new.zip
Press enter, then wait until it has completed. After that, go to finder -> Go -> Home -> MacNoEditor->ProjectTetraAlpha
Thanks for your patience!
ProjectTetraDev