Whenever someone mentions last-minute changes in movies, fans get a little panicky. It's understandable since the term has become synonymous with train wrecks in recent years. In the case of comic book movie fans, they're heavily invested in these heroes and villains and don't want to see them ruined on the big screen by greedy studio execs.

It isn't all doom and gloom, though, as changes are part and parcel of the movie industry. Every production is riddled with its own problems and there's often a necessity to adapt and tweak at unplanned times. Sometimes, these adjustments arrive at the most inopportune moments, but you have to go with the flow.

In fact, we've seen several instances where these changes have worked out for the best and improved the final product, while we've also seen the reverse where the worst possible outcomes panned out. One thing is for certain, though: no matter how much we protest, last-minute changes are here to stay, so it's best that we take a deep breath and get used to them.

So, with that said, let's take a trip down memory lane and look at the 10 Last-Minute Changes That Hurt DC Movies (And 10 That Saved Them).

Hurt: Joss Whedon Taking Over Justice League

Justice League final battle Russia

Zack Snyder stepped away from Justice League due to tragic circumstances mere months before the film's release. At the same time, it was announced that Joss Whedon would take the production over the finish line. According to producer Charles Roven (via CinemaBlend): "[Whedon] was already working with us on some of the scenes for that additional photography. It was fortunate that Zack convinced him, and he agreed to step in and finish the movie."

It wasn't that simple, though. Whedon and Warner Bros. reshot most of the movie, and it's obvious that the final product was a stitched and rushed job to meet its release date. Watching Justice League, it's a tale of two movies – and Whedon didn't win DC fans over for tampering with Snyder's vision.

Saved: Superman's Script Rewrite

Christopher Reeve as Superman smiling while standing in front of a city skyline in Superman

Richard Donner says that producer Alexander Salkind called him out of the blue and offered him a million dollars to direct Superman. An hour after the call, a delivery man arrived at his door with the script. "So I sat down and read the script, and it took forever. It was the longest thing I have ever read. It was indulgent and heavy and had no point of view and treated [the comic books] with disrespect," Donner told The Hollywood Reporter.

Disappointed, but not about to turn down the money, Donner called writer and friend Tom Mankiewicz, who eventually agreed to rewrite it. At first, the studio didn't agree to a script rewrite, but after an argument, it finally caved in to Donner's wishes.

Hurt: Michael Keaton Leaving Batman Forever

Batman-Forever-Val-Kilmer

Much like Richard Donner's Superman changed the superhero film landscape in the '70s so did Tim Burton's Batman 11 years later. When the sequel, Batman Returns, went a little darker than what Warner Bros. expected, there were major disputes about the direction of the movie that would end up becoming Batman Forever.

Burton departed the project, and he was followed by the franchise's star, Michael Keaton. The latter's departure was a bitter blow since he'd become synonymous with the role and is still ranked as one of the best actors to put on the cape and cowl. "[The script] sucked. I knew it was in trouble when [Joel Schumacher] said, 'Why does everything have to be so dark?'" Keaton told The Hollywood Reporter.

Saved: Maggie Gyllenhaal Replacing Katie Holmes In The Dark Knight

Rachel Dawes smiling in The Dark Knight

It's safe to say that there was zero chemistry between Katie Holmes' Rachel Dawes and Christian Bale's Bruce Wayne in Batman Begins. So, when Holmes turned down the opportunity to reprise her role in the genre-defining The Dark Knight, she was replaced by Maggie Gyllenhaal.

Holmes must feel a little aggrieved as the role of Dawes played a significant part in The Dark Knight and featured in all of the movie's best moments. Additionally, Gyllenhaal developed terrific on-screen relationships with both Bale and Aaron Eckhart. What must hurt Holmes even more is that Gyllenhaal's career continued to ascend after this film, while her most famous role still remains as Joey Potter in the '90s teen drama Dawson's Creek.

Hurt: Richard Lester's Superman II

Superman 2

When envisioning Superman on the big screen, Alexander and Ilya Salkind decided that it would be a two-movie deal to begin with. The two movies would be filmed back-to-back, saving time and allowing for quicker release dates. Unfortunately, with the budget soaring on Superman, the producers decided to let Richard Donner focus on getting the first movie out.

Considering that Superman was a massive hit, you'd think the Salkinds would get Donner behind the camera as soon as possible to wrap up Superman II, but that wasn't the case. There had been numerous fights between director and producers, so they decided to replace him with Richard Lester – even if 75% of the movie had been already completed by Donner. Decades later, the Donner cut proved far superior.

Saved: Michelle Pfeiffer Replacing Annette Bening In Batman Returns

Selina Kyle (Michelle Pfeiffer) in her Catwoman suit looking through a window in Batman Returns

The casting of Michelle Pfeiffer as Selina Kyle/Catwoman in Batman Returns is an example of what happens when the stars align. "I was halfway through the script when I said yes," Pfeiffer told Empire Magazine (via The Wrap). "Someone else was cast in the part and I being absolutely devastated and calling my agent and saying, 'How have I not had a meeting about this? Why have I not heard about it?'"

The actress was Annette Bening. Pfeiffer, though, was considered as a backup. Things worked out for her in the end as Bening had to depart the production due to her pregnancy and Pfeiffer received the role. Looking back at it now, it's impossible to imagine anyone other than Pfeiffer as Catwoman.

Hurt: Shortened Batman V Superman's Theatrical Cut

Mech Batsuit Batman v Superman

The story of Batman v Superman: Dawn of Justice would make for an interesting book. Reportedly, one of the movie's test screenings received rapturous applause, yet the final theatrical release was met with a lukewarm response. It didn't make matters any better when the Ultimate Edition proved to be a far superior film than the theatrical version.

As it turns out, we have Warner Bros. to blame for tinkering with the theatrical cut. Speaking to Collider, director Zack Snyder said, "It was really just a function of time, to be honest. Because the movie's long now, long-ish – I don't think it's long, but when you get over two and a half hours the studio starts getting nervous."

Saved: Cillian Murphy Being Cast As Scarecrow In The Dark Knight Trilogy

Cillian Murphy as Scarecrow wearing his mask in Batman Begins

Thinking back to Batman Begins, one of the most inspired casting choices was Cillian Murphy as Dr. Jonathan Crane/Scarecrow. There was a real menace and mystery to his rogue, and we got to see him appear in the entire trilogy. Things could've been different, however, had Murphy received the coveted part he originally auditioned for.

Chatting to The A.V. Club, Murphy discussed how he auditioned for the part of Bruce Wayne/Batman. "In fact, I did an awkward audition in the Batsuit. [Laughs.] I think [Christopher Nolan] saw something interesting in that screen test somehow, though, because he said, 'Hey, would you be interested in playing this other part?' Then we did a lot of work."

Hurt: Suicide Squad's Edit

Suicide Squad - Margot Robbie as Harley Quinn

Amazingly, after interfering in the theatrical cut of Batman V Superman: Dawn of Justice, Warner Bros. thought it was a good idea to do the same to Suicide Squad. It also didn't help that the studio only gave David Ayer six weeks to write the script and rushed the movie into development.

According to The Hollywood Reporter, multiple editors were used and Ayer was even locked out of the editing room at some stage. While the director has remained polite and praised the studio for affording him the opportunity, he's also itted that the final version of the movie isn't what he envisioned. The question is, will we ever see the Ayer cut of Suicide Squad?

Saved: Ben Affleck Not Directing Man Of Steel

Man of Steel

Right now, no one knows if Ben Affleck is still in or out as Batman. There's a lot of debate and murmurs doing the rounds, but Warner Bros. hasn't released any official statement. As it turns out, his participation in DC films could've been a whole lot earlier – but not in the way you expected.

Before deciding on Zack Snyder as the director of Man of Steel, Warner Bros. developed a shortlist of directors including Snyder, Darren Aronofsky, Duncan Jones, Tony Scott, Matt Reeves, Jonathan Liebesman, and Affleck. Reportedly, Affleck turned down the offer. It's a good thing that he did, though, because it's unlikely we would've seen him as the Caped Crusader had he directed the movie.