With Avengers: Infinity War poised to become the first summer blockbuster to reach $2 billion at the global box office, the massive Marvel Cinematic Universe ensemble film seems like a success by all accounts. However, writers Christopher Markus and Stephen McFeely wish there was one big thing they could've changed about the story -- or, rather, six big things.

"Had we started from scratch, we would not have chosen six damn MacGuffins," McFeely told The New York Times. "That’s not that helpful. It was difficult to get that all in."

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The six MacGuffins -- or tangible plot devices whose primary function is to drive the narrative forward -- in Infinity War are the Infinity Stones that power the Infinity Gauntlet used by Thanos in the film.

The six Stones, each of which represent a different cosmic energy, drove the overarching narrative of the MCU. Following the introduction of the Space Stone in 2011's Thor, the Mind Stone was introduced in 2012's The Avengers, the Reality Stone in 2013's Thor: The Dark World, the Power Stone in 2014's Guardians of the Galaxy, the Time Stone in 2016's Doctor Strange and the Soul Stone in Infinity War. Each Stone teased bigger things to come, building up to the events of Infinity War.

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Having the Avengers sequel serve as the culmination of the MCU meant Markus and McFeely had to make sure each of the six Stones got their respective attention, which could have proved unwieldy in lesser hands. While certainly a logistical headache to insert organically into the story, Infinity War's commercial and critical success proves that the writers were more than up to the challenge.

In theaters now, Avengers: Infinity War is directed by Joe and Anthony Russo and stars Robert Downey Jr., Chris Evans, Chris Hemsworth, Mark Ruffalo, Scarlett Johansson, Paul Bettany, Anthony Mackie, Elizabeth Olsen, Tom Holland, Benedict Cumberbatch, Chadwick Boseman, Chris Pratt, Zoe Saldana, Dave Bautista, Bradley Cooper, Vin Diesel, Tom Hiddleston, and Josh Brolin, among others.