7. War of the Worlds (2005)
The Twist: Earth is invaded by aliens for Mars, and Tom Cruise goes on the run with his annoying children for a couple of hours, only to find that... wait, simple bacteria has stopped the aliens dead in their tracks (as in... they're all dead), and the world goes back to normal.
Why It's Unpopular: Bacteria killing the aliens is horribly anti-climatic. Couldn't Spielberg have thought of something a little bit more exciting than that? You know, like he did when he put that tank in the shark's mouth for the climax of
Jaws.
Why It Deserves More Credit: Because it's genius. And aside from the fact that it's genius, it was also in the original novel in H.G. Wells, who opted for a scientific and realistic approach to the human race having somehow beaten the Martians, who have heat rays and mechanical tripods. Fact is, the Martians are in possession of technologies far superior to our own, but they completely overlooked an aspect of their invasion that we, too, take for granted on an everyday basis: bacteria. We've built up an immunity to bacteria over millions of years, of course, whereas newcomers have no defense against it at all. Many said it was anti-climatic to end the movie in this way, because they wanted Tom Cruise blasting fighting an alien with his bare hands on top of a tripod, but the ending we got is logical and super clever and you can't convince me otherwise.