(You have to watch this slipup in slow-mo; otherwise you wont see it!) Towards the end, when Vader and Luke are fighting, Luke does a summersault flip backwards on to a higher platform. Then, Vader throws his lightsaber at Luke. Just before the lightsaber crosses Luke's face and is about to exit the screen, you can actually see the blade, either: A) Bend a large amount up towards the roof, or B) Actually come out of the handle!