Dev Patel is transfixing. The visuals are unmatched. Absolutely worth seeing on the big screen and I highly recommend sitting towards the front of the theatre to appreciate the attention to detail. It follows the story of Sir Gawain and the Green Knight, but it is not a direct reading of it. A fascinating interpretation - the final ten minutes blew my mind.
As others have said, do not watch this film expecting it to be gore-y like 300 or action-driven like recent super hero films.