movie review BACKROOMS Running time: 105 minutes. Rated R (some violent content, language, bloody images). In theaters. Hollywood trembles in fear of the havoc the internet has wrought and will continue to wreak on its core business. Execs wake up in a cold sweat from a nightmare that blockbusters have been replaced by 30-second TikTok videos. And, yikes, they almost have. But perhaps the key to a prosperous future is collaboration.  Enter “Backrooms”: a disquieting and smart new horror film