As someone who has watched all of the Overlord series to date, I enjoyed this as a quick condensed form of re-watching season 1. It doesn't add much, a few more animated scenes and an extra line or two, perhaps. Don't watch it expecting any new content, it cuts through a lot of the fluff of season 1. Only the pivotal exposition scenes have remained, and most of the action. As for whether an unfamiliar audience would enjoy the film, I think it leaves out too much of the initial story building of Nazarick and the E-Rantel region to properly introduce viewers to the series.I would still greatly recommend watching the first season instead of this if you're looking to get into the series, since this gives you the bare minimum in explanations and feels rushed, but the film is still decent in its own right.