I've been having problems with the DS version of Lego Star Wars, as it seems to be loaded with glitches (which most reviews have noted). I've been able to work my way around most of them, but during the escape from the death star when i have to fight vader, he seems to be invincible, and i spent a good 15 mins trying to kill him. Can anyone tell me how the fight is supposed to go, so i can figure out what i'm doing wrong?