From the discussion at "When did Opening Credits become Closing Credits?", we learn that "the use of closing credits in film to list complete production crew and cast was not firmly established in American film until the 1970s. Before this decade, most movies were released with no closing credits at all."
What is the most recent Hollywood feature-length film not to contain closing credits at all? Since the 1970s, have there been any "retro"-style movies that used opening credits only, similar to how we nowadays see the occasional modern film that is silent or black-and-white (or both)?
