Well, let's get serious.
One other movie which I thought had an anticlimactic ending/death was Dark Shadows
. I don't know if anyone has seen it, but ...
Towards the end, Johnny Depp's character Barnabas Collins was trying to save the reincarnation of his former love, Josette, in the present body of Victoria, whom the evil witch Angelique Bouchard cast a spell on to jump off the cliff in the same manner that Josette did. As Victoria and Barnabas plummeted to the rocks below, Barnabas bit Victoria just before they hit the bottom, transforming Victoria into a vampire. Meanwhile, the Collins family just watched as their manor burned to the ground. I thought the ending could've been a lot better by showing what would become of Barnabas and Victoria and the whole Collins clan