The one thing that the series does is dip its toe into all the different type of genres that make up Heavy metal.
I too don't like all aspects of all genres ( it's an age thing I guess) but its fascinating to see what a diverse and creative world HM was, is, and how it all developed.
Lack of progression is something that all the detractors of HM music always bang on about. They ought to watch this series!

Well said.