(Image credit: A24) Tom's Guide Verdict: 'Backrooms' Rating: 4/5 stars Verdict: "Backrooms" may be adapted from a YouTube series, but it's made for the big screen. The performances are excellent, the tension is perfectly crafted and the set design is genuinely an art form. But the ending leaves you with just enough questions to slightly sour the experience. Where to watch: See "Backrooms" in theaters now "Backrooms" made our list of the biggest summer movies to watch this year, and going into it, it was easy to see why. Yes, it's director Kane Parsons' first feature-length film, but it stars Oscar nominees Chiwetel Ejiofor and Renate Reinsve. It's produced by James Wan, Osgood Perkins and Shawn Levy. Sure, it's an adaptation of a YouTube series, but guess what? That's in right now. "Iron Lung" was a hit earlier this year, and " Obsession " made more money in its second week in theaters than in its debut. In short, being in the YouTube horror genre is a selling point for this movie, not a shortcoming.…