True appreciators of horror films have long been attracted to the genre as much for its humor as for its more grizzly aspects. The overused and thus hilariously predictable tropes, the (sometimes) cheesy special effects — the macabre, as it turns out, can be pretty darn funny. It’s sort of like how Halloween, for all its spookiness, can be seen as really all about release, laughter, joy and silliness. This is where Redrum comes in. The sharp and cheeky, savage and silly improv production — which is directed by Jay Rodriguez and stars Fálki Heiđdottir, Andrew Jaxling, Mitchell Murphy, Juan Torres and Andre Villaplana — finds performers, inspired by the great/terrible horror films of the 1980s and 1990s, making it up as they go along, with some opportunities for audience input. Since timing is so integral to the execution of a horror piece, you can imagine just how humorously awry things can go with an unscripted performance like this. The events of the play follow a cast of stock, teen horror movie archetypes, “The Jock, The Nerd, The Party Girl and The Virgin,” as they try to survive the advances of a killer on the loose. The show, which first ran on October 5 and 12, will also run on October 26.