I guess this is a sequel to two other probably identical movies so once again people return to the dreaded Abbadon hotel where all that stuff happened, this time to shoot a documentary about other people doing a reality show about people putting on a production of a cursed play, so multiple layers of found footage of found footage.
Oh my god there's a person in the background of the footage. That's pretty much the movie. I guess we have to admit at this point that found footage isn't just a flash in the pan; it's a full blown persistent genre of horror and even has subgenres now. This is the subgenre that doesn't have monsters, just people who aren't supposed to be there. Sometimes they have bloody makeup, sometimes it's just regular guys standing in the shot. I think they might be ghosts of people killed in the other movies. If so this movie should make it more obvious because if like me you haven't seen the others it's pretty important information in order to understand that there's anything unusual about these people being seen on video.
Somehow the performance of the play opens the gates of Heck and a demonic horde of half a dozen guys in black cloaks pour into our dimension and assault people but the invasion is pretty well contained inside the hotel and everyone seems to be okay at the end and got quite a bit of video. It's another hour and a half of the same really long movie that is this entire genre.
I wonder if twenty or thirty years from now we'll have nostalgia for these things. I could criticise them for being repetitive and formulaic but I have to remind myself that I'd be happy to watch a hundred almost identical Friday the 13th sequels. Movies don't have to be original if they show us something we like, and I guess a lot of horror fans really like seeing stuff caught on video. So it's fine. It's a horror movie, it pulls off a couple decent scenes, doesn't waste a bajillion dollars. I don't know what else to tell you. I read somewhere that there are over 900 horror movies released every year now. This was one of them.