In this Unity tutorial series, newly updated for Unity 2018.1, you'll learn how to make your first game in Unity with C# from scratch: a twin-stick shooter called Bobblehead Wars!
That sounds like something is corrupted. I would suggest downloading the assets again. If that doesn’t work, then feel free to reach out to me at brian@razeware.com. I can send you the assets or a starter project with the assets included.