I have found a solution based on Felicja’s solution.
Mac users need to allow apps downloaded from “Anywhere”.
To do so:
apple > system preferences > security and privacy > click on anywhere at the bottom.
Afterwards, go re install the update: http://cider.ncplatform.net/Live/GWII-Update-009524.tgz
Then go on game and test it out. Worked for me. And also, please leave the setting at security pref to “Anywhere”, as that kind of screwed me over when put back on mac and identified devs… hope it works.