Two years ago, filmmaker Jeremy Saulnier brought a little movie called Blue Ruin to Directors' Fortnight at Cannes. It was a hit, soon making its way to U.S. theaters. Now, Saulnier returns to the section with Green Room, which pits a punk band against a scary group of skinheads (including one played by Patrick Stewart). Not nearly as nuanced as Blue Ruin, Green Room is straight-up B-movie pulp. It's pretty well done, as I explain in my Screen International review.