The barroom scene and the missile scene both contain visual references to scenes from Star Wars.
When the Doctor is being 'rescued' by the cactus people, who haven't bothered to untie him, he shouts "Worst Rescue Ever!" This is a reference to The Simpsons' Comic Book Guy's catchphrase "Worst *blank* Ever!"
William Hartnell tearfully tells his wife "I don't want to go" after announcing his departure from Doctor Who. These were also the last words spoken by the Tenth Doctor.
A couple of teaser clips.
A clip is shown