Sounds like an expensive oversight.
I didn't buy the 4k disc of Hell of.., as I'd never seen it before and so I bought a used bluray in CEX last month for £6, I loved it, but it doesn't seem the kind of film that would need to look any better, and there is so much stock footage used. I did buy the Cannibal Holocaust one though which looked brilliant. Listened to the Kim Newman and Barry Forshaw commentary track which was amusing lol.
__________________  Triumphant sight on a northern sky |