Professor just gave an exam that was way outside of the scope of the class, various other issues with assignments, what should the class do?
Actually, I don't think there is much you can do. Professors and administration hear complaints about "unfair" or "too difficult" exams all the time and most of them are exaggerated. 

If your university has some official representation of students, you should go to them so that they can bring up the issue at an appropriate place. And you can hope that the professor sees that the results of his exam are very poor and that he reacts to it.