The small, deft Gruesome Playground Injuries duels with your emotions like an expert fencer. Each brief scene is a moment between Doug (the boyishly charming Richard Nguyen Slonkier) and Kayleen (a dark and intriguing Amanda Zarr) at a moment of injury—sometimes physical, sometimes emotional, and often both. It opens with them meeting in a school nurse’s office at 8 years old and ping-pongs through their adolescence and adulthood while they rack up several decades’ worth of scars. (Azeotrope at Little Theater, 608 19th Ave E, brownpapertickets.com, 2 and 7:30 pm, $25)