It's not the last 15 minutes, but Hot Fuzz has an amazing shift in tone.

The Sound of Music, surprisingly. The first like 90% of the movie is them singing and frolicking through fields, then it ends with them being chased by nazis. It's such a radical shift in tone.

Cabin in the Woods

Bone Tomahawk is a great example of this even if not necessary the last 15 min. Most of the movie is a pretty ok western. Bad stuff starts happening and it's still a pretty ok western. Then there is 1 specific scene that goes so hard, you'll want to forget you ever laid eyes on it. Then it's back to western movie but now you have to remember the shit you just saw 🤣

Hereditary

Jojo Rabbit goes from a heartwarming dark comedy about a boy that is living through WW2 and his imaginary friend, Adolf Hitler, into something very different that is too much of a spoiler.

From Dusk Til Dawn

Once Upon A Time In Hollywood. It felt like mostly nothing happened for 2 hours. There was some decent dialogue and a lot of references to 1950s and 60s Hollywood. There is some build up, but not much payoff until the last 20 minutes. Then everything goes off and you are reminded that this is a Tarantino film.

I would argue seven doesn't go from 0-100 in the last 15 mins once the first murder happens its takes off from there

Not the last 15 minutes, but Sunshine really takes a turn.

Maybe mother! I feel like it gets exponential more chaotic towards the end but that might take place over more than 15 minutes

There will be blood

The mist, which I think was a Steven King book first I think.

The Incredible Weight of Massive Talent

not a movie but a show - Pantheon. It has 2 seasons, 16 eps total. But the last 2 eps cranked the intensity and scale up to 1000.

Parasite.

Maybe even Joker.

I feel like paranormal activity fits this. Most of the movie is pretty light with activity until the end when it ramps up.

Return to Sender (2015)

The ending is 0 to 100 fucking insane. It’s like Rosemund Pike decided that she wanted to make a Gone Girl 2. It’s a horrible film, but incredibly memorable due to that crazy ending.

Parasite went hard after they discover the hidden network in the house

Hateful Right comes to mind

Some of these are debatable, just went through my collection and considered the ones that I remember having an exciting end.

Akira, Burn After Reading, Children of Men, Chronicle, The Departed, The Room (unironically), Smile (maybe? The whole movie is kind of building anxiety attack), There Will Be Blood

House of the Devil. And it's fucking awesome.

Studio 60 on the Sunset Strip. It's a Sorkin TV series that was interrupted by a Hollywood writers strike and cancelled so they had to wrap it up. And it was an amazing ending.

A Cure For Wellness goes from a slow burn mystery/thriller into a B-movie shlockfest in the 3rd act

I swear once he found out what the treatment was and he was given it, that the movie was over, cut to credits, fin. But there's another half hour after that, and it's wacky.

Only The Brave.

If you go in without knowing the story, it starts off like the plot arc of a sports movie:

• An outsider joins, and struggles to fit in with a close-knit team
• The team is trying for a promotion
• We see teaching of the team's methods
• Victory at a smaller event
• Outsider is accepted as part of the team
• Long period of training for the big event

Unlike the sports movies, the last few minutes of this are not at all victorious...

No One Gets out Alive

Although that's more like it goes from 75 to 10,000 in the last few minutes.

The rental. It goes from being a drama into a horror hard at the end.

I would say, the Invitation. It's quite slow, a bit bizarre in its set-up, and took me years to watch it after checking it out once and thinking "This is the movie people are excited about?"

But hang in there for the last 25-30 mins, and it really pays off. I think about it all the time now.