I would be incredibly surprised if I read a play worse than Titus Andronicus in this challenge. Titus was Shakespeare's first attempt at staging a classical tragedy - something which he will eventually go on to get so right in works such as Julius Caesar. The basic plot follows a Roman general (our Titus) who is victorious in a battle against the Goths. As a reward Titus brings the queen of the Goths and her sons back to Rome. Titus is a silly billy however because he kills one of the queen's sons and then the queen plots revenge on Titus. Nobody cares about the plot of Titus however. Any piece of criticism you read about this play will mention the same thing; its bloodiness and its violence. Titus is such a violent play that during the Victorian era it was practically banished Shakespeare's oeuvre because the Victorians couldn't handle the play's unrelenting gore. This might sound enticing to some but believe me, it isn't as fun as it sounds. 
 Titus Andronicus reads like Charlie Manson's rejected screenplays. The word "gratuitous" doesn't even begin to describe utter violence of this play. Macbeth is bloody and violent but it is also a perfectly constructed narrative in which every drop of blood has a clear motive and consequence. There's a character in Titus who is raped and then her hands and tongue are cut off. She doesn't die however, she sticks around for two more acts just fumbling and making garbled noises like Brendan Behan at an open bar. I lost count of how many amputations take place in Titus by Act 3. 
 Poet and cat enthusiast, T.S. Eliot, once wrote that Titus was 'one of the stupidest and most uninspired plays ever written'. Whilst Eliot might have been fond of the odd hyperbole I cannot help but agree with his sentiment. Titus, as far as I can see, has absolutely no redeeming qualities. It's the Elizabethan equivalent of Viva Forever!: The Spice Girls Musical. In fact, the history of criticism on Titus seems to just be a duel of insults as each critic attempts to formulate the ultimate put-down or the sickest burn. One of my favourites is from token white critic Harold Bloom who suggests that the violence and tragedy of Titus is so comically absurd that the best director to tackle the play would be Mel Brooks. (I am biased toward loving anything Harold Bloom writes because he once called slam poetry 'the death of art'.) 
 At least I now have an answer for when someone asks me what Shakespeare's worst play is. I didn't even tell you about how two guys literally get baked into a pie. Oh Titus Andronicus, you precious mess.