I agree. People need to realise the market that this guy was targeting - it is average Joe on the streets, not the HN nerdy types. I know a fair amount engines and how they work, I still think it's very informative. The guy is a self taught graphic designer that judging by his portfolio works mainly with Photoshop. Instead of some people complaining about "it should be tech X or tech Y", maybe reach out to the guy and try to work with him.

I'd like to see one on airplane and jet engines next :)