Warning: MAJOR SPOILERS for Doctor Strange are ahead!
Although Doctor Strange threw in the trademark explosive battle that are standard near the end of most superhero movies, the final conflict actually didn't involve fisticuffs or energy blasts. Using the Eye of Agamotto, Stephen Strange entered the Dark Dimension and trapped himself and Dormammu in an infinite loop until the latter agreed to leave Earth alone. Before that happened, Strange was killed but the entity several times, and a line from an earlier draft explicitly said that he'd been put to death at least 1,000 times, making the situation signifcantly more intense.
Director Scott Derrickson recently told Empire that in one of the earlier Doctor Strange drafts, the eponymous hero specifically revealed how long he and Dormammu were trapped in that never-ending time loop. Derrickson explained:
Yep, that can definitely be categorized as the superhero version of Groundhog Day. For those who need a Doctor Strange refresher, when Stephen Strange and Mordo arrived in Hong Kong, Kaecilius and his followers had already opened Earth up to the Dark Dimension. Stephen wound back time to undo the Sanctum's destruction and the deaths of everyone nearby (including Wong), but the Dark Dimension continued to swallow up everything nearby.
To put an end to the destruction, Stephen ventured into this other reality and set a time loop before he came to Dormammu to bargain for Earth's safety. The entity wasn't in the mood for discussion and immediately killed the sorcerer, but thanks to Stephen's skillful use of the Eye, they were stuck in the same moment over and over again. The movie showed approximately a dozen of these loops (I'm not sure about the exact number), but there was nothing to indicate that the two of them have gone through this routine 1,000 times or more. Nevertheless, eventually Dormammu agreed to Doctor Strange's demands in exchange for ending the torture.
This was by far the weirdest use of time manipulation in Doctor Strange, and it might have been nice if Scott Derrickson had kept that 1,000 times line in to reiterate the ultimate sacrifice the main hero was willing to make to keep Earth safe. Fans can also take solace knowing that this won't be the last time the Eye of Agamotto will be put to use. After Stephen Strange left the Eye behind at Kamar-Taj, Wong revealed that the item was one of the Infinity Stones. With Avengers: Infinity War on the way, eventually Thanos will obtain the Time Stone, and unfortunately, he'll probably screw around with its abilities in a malevolent way.
Doctor Strange is currently showing in theaters, and make sure to keep up with our continuing coverage of the movie here.