Director Frank Merle’s adaptation of Shakespeare’s greatest tragedy for the Keyhole Theatre Company is shorter but strangely labored. Unthinkably, he omits the play within the play–a pivotal scene in which psychosexual tensions and revenge fantasies collide and are transformed into palpable menace. A few judicious cuts elsewhere cure the characters of their nasty habit of overexplaining themselves, but many of the nuances get lost too. If we’ve learned anything from Law & Order, it’s that every crime has a motive, and in the absence of complex characterization here, the second-act violence seems particularly senseless as the body count rises. Period costumes are an odd choice in a staging that’s otherwise no-frills, and Merle’s performers appear a little lost within the blank walls of the black-box space. Still, their enthusiasm for the material–aided by all the stabbing–is infectious. Through 2/20: Fri-Sat 8 PM, Sun 7 PM. Josephinum, 1501 N. Oakley, 773-805-5055. $15.