At the very least I feel I should watch Hereditary and Midsommar back to back because they seemed like perfect companions, the male and female sides of, largely the same story. I still haven't been able to discuss this idea with anyone because everyone's focusses on how Midsommar is such a great feminst power yarn.
Okay, that's done. Here are the similarities: Vulnerable boy (Hereditary) and girl (Midsommar) lose parents and a sister and find new family in satanic coven (Hereditary) or pagan (Midsommar) community through becoming host to King Paimon (Hereditary) or the May Queen (Midsommar). Watching both films' making-ofs, Midsommar was in process during the making of Hereditary such that Hereditary opened 8 June 2018 and Aster and crew were on location 9 June 2018 and shooting in August. I think it's reasonable that
ideas from Hereditary found their way into Midsommar; in fact Midsommar has at least two
scenes, I know for a fact were taken from Hereditary.
Aster admits in the Midsommar making-of that it is a loose companion to Hereditary in that both films are about family and codependency. But I think it's deeper than that. The demons of Hereditary are real, they are not metaphorical. Likewise, Midsommar is far more than a mere breakup movie, as Aster (via Pugh) asserts.
I'm glad I watched them back to back for a circumspect analysis, but there were both even more perverse and wicked than I had remembered. They are well made-- acting, costumes, set, direction, are all top notch --but they are unwholesome and unhealthy. No one needs that much exposure to the occult. Watching Midsommar's rituals made me so thankful that Jesus died and rose to save us from this, that the pagan gods really are, truly dead. I cannot recommend these films.