Rightfully so, most movies put the majority of their effort into ensuring that the protagonist's journey is the most satisfying and punchy narrative thread the story has to offer, giving the film a solid foundation off which to build everything else.
And while this works well most of the time, one possible side effect of spending so much time on the hero can be a villain who is sorely underdeveloped, or frustratingly, a villain who has a pretty good showing for two-thirds of the runtime, only to drop the ball right at the finish line.
Whatever the reason - a desire to keep the plot speeding towards its conclusion, a simple case of bad judgement, having to nerf someone who's too powerful - a lot of movie writers give their bad guys send-offs that are either rushed, too easy, or annoyingly underwhelming, even when they've already shown how badass and dangerous they can be in previous confrontations with the hero.
Sure, a lot of these antagonists are still great as a whole, but their endings left a lot to be desired, and they really should've gone out with a bit more of a fight.
10. The Final Clone (Gemini Man)
Near the end of Gemini Man, Henry Brogan and his younger clone randomly team up to take down the shady Clay Varris and his army of GEMINI operatives. Just when it looks like they've won, they're attacked by yet another clone of Brogan, one who feels no pain and has had most of the humanity sucked out of him in a lab.
While it's true that this particular clone takes a hell of a lot of bullets to finally defeat, the fact that it only takes Brogan and his allies two or three minutes to bump him off reeks of a screenwriter who realised that they'd introduced a powerful antagonist far too late in the game, and needed to wrap things up quickly.
For the first 90 minutes of the film's runtime, Brogan has great difficulty in escaping from and defeating the first clone, who - due to the fact that he feels pain and shows emotions - is an inferior soldier when compared to the final clone. 90 minutes fighting the lesser clone... three minutes fighting the powerful clone. See the issue here?
Defeating the final clone so quickly essentially undermined the whole point of the movie: that Brogan's clones are the best of the best, and require a feature-length runtime in order to take down.