Originally Posted by Habakuk
I read the ten last pages or so in this thread but the IAPs aren't mentioned anywhere (and the tA search can't find "IAPs" in this thread). Is it because they are completely optional?
If the IAP's are only for helmets (and I haven't checked my game recently to see if anything else is added), then they are completely optional. The helmets let you skip a tough level, but since all the solutions are available online it's really only for those who can't use Google.
Or for those who want to support the developer of this fantastic game! I see it as more of a tip jar.