LOL Gamera 3 is one star.
I love Showa Gamera films,so I think I have a pretty good idea of what to expect when watching one,I don't set my expectations too high,or expect an "adult" or "serious" film. With that said,Gamera vs. Viras is terrible. There's no excuse for SO much of the movie to be stock footage of the fights from other films,basically in their entirety. I'm sure you could make an argument as to why the stock footage is in there,or that it's still entertaining,but in my mind all arguments are over and all excuses are used up when part of the film becomes black and white.
Let me state again,that this is a color movie,which for no reason explained to the viewer,(i.e. you have to know about the stingy budget in order to understand) becomes black and white for awhile. If I didn't know better I'd return my DVD to the store because it was broken!
Again, Gamera vs. Guilion is one of my favorite movies,and I've watched and enjoyed all the other Gamera films (except Super Monster Gamera) so it's not that I'm not "in the right mindset" or however you want to phrase it.