A bitter end to a very dark and quite dull Harry Potter movie. There were other worthy cliffhangers across the franchise, such as the return of Lord Voldermort at the end of The Goblet Of Fire or Dobby's death at the end of The Deathly Hallows - Part I, but none had quite the impact as the dramatic ending to the sixth entry. Snape killing Dumbledore was a huge blow to Harry, his friends and allies. Up to this point the potions master had always proven to be a good guy, despite his aggressive behaviour towards Harry, but this terrible act changed things. While he would ultimately be proven to be working against the enemy, taking out the only wizard Voldermort was scared off was a huge turning point in the wizard war and the movie franchise. Harry Potter And The Half-Blood Prince was the last film to be based around the school year at Hogwarts, meaning the cliffhanger really shook things up dramatically, raising the stakes for the two-part finale. It was The Empire Strikes Back of the Harry Potter series. The good guys loose badly and suddenly audiences wondered how Harry, Ron and Hermione were going to get out of this war alive, let alone defeat Lord Voldermort.