Somehow it managed to be even stranger and trippier than I expected. Watching it after only getting 4 hours sleep the night before was probably not the best idea, but it did add to the dream-like quality of it all. Especially liked the long, wordless sequence at the end. Need to see it again when I'm more awake.
Additional observation: I have read Sir Gawain and the Green Knight twice in an academic setting, once in 10th grade, another time in college. I have to wonder how people unfamiliar with the original will take to this film, as so little is explained or made explicit.