The X-Men movies reign as some of the most original comic book films. From 2000’s X-Men to 2017’s Logan, the franchise has succeeded as both the longest running and the most idiosyncratic comic book franchise. Some of the films are so different from the others that they fall into entirely different genres. The Wolverine was essentially a Japanese samurai film, while Logan was a full-fledged Western. X-Men: First Class was a dramatic coming of age story, while its follow-up, X-Men: Days of Future Past was a futuristic dystopian thriller.

The X-Men movies have run the gamut of genre storytelling. While this has made for some great flicks, it has also caused many inconsistencies throughout the franchise. From continuity gaffs to errors in logic or judgment, the X-Men movies are filled with mistakes. This has a lot to do with the change in directors and screenwriters from movie to movie, and an apparent lack of interest in keeping the facts straight. Even with Bryan Singer, who’s directed the most X-Men films, there are still some bizarre storytelling hiccups between his earlier and later installments. Whether the error lies in continuity, storytelling, adaptation or directing, there are plenty of mistakes to be found in the X-Men movie universe.

15 HOW JEAN GREY BECOMES PHOENIX (X-MEN: THE LAST STAND)

Much ado has been made about how The Last Stand screwed up its source material. The most glaring example is the transformation of Jean Grey into Phoenix. In the comic books, Phoenix was a cosmic entity who took over Jean’s body. In the film, Jean was consumed by an alternate personality who called itself the Phoenix.

This was a frustrating change, particularly in the throw-away rationale behind the name ‘Phoenix.’

The name has significance in the comics, because the cosmic being takes on the shape of the regenerating bird. In the film, it’s just a catchy name. Admittedly though, in the context of the film, the split-personality angle works pretty well. It’s a scientific explanation that’s in-keeping with the tradition of the other X-Men films. Phoenix as an alternate personality works for the film, but it falls disappointingly short of the cosmic magnitude achieved in the comic books.

14 MUTANTS ARE EXTINCT (LOGAN)

It’s hard to criticize 2017’s Logan for anything. It’s in Logan’s connection to the larger X-Men franchise where flaws begin to emerge. Chief among them is the film’s complete dismissal of X-Men: Days of Future Past. The 2014 film began with a dystopian future where the mutants are nearly extinct. But Logan goes back in time and restores mutant kind. Three years later Logan comes along, and guess what? It takes place in a dystopian future where the mutants are nearly extinct.

Maddeningly, it’s Wolverine himself who drives both stories, yet in Logan there's no mention of what happened. Since Logan is the only one who remembers the old timeline, his apparent failure should have made him very, very bitter. A single begrudging mention in Logan would have helped resolve the discrepancy. Unfortunately, as with most mistakes in the X-Men movie continuity, Logan elected not to address it at all.

13 WOLVERINE'S MAGIC CLAWS ( X-MEN: DAYS OF FUTURE PAST)

X-Men: Days of Future Past tries so hard to fix the X-Men series’ timeline inconsistencies. When the future X-Jet disembarks on a gloomy platform, Wolverine emerges with the remaining X-Crew. He ejects his claws, revealing a shiny and perfectly maintained adamantium skeleton.

There’s just one little problem with this -- the last time we saw Wolverine, he had all three claws stomped right off.

In the final battle of The Wolverine, Logan has the claws completely broken off his right hand by Silver Samurai. At the end of the film, we see that his claws have re-grown, but they’re his original bone claws. In the very next film, Logan’s adamantium has miraculously re-sealed over his skeleton. To have the opening of the immediate follow-up completely ignore this seems lazy, particularly since Days of Future Past is specifically designed to rectify the series’ inconsistencies.

12 XAVIER'S PARALYSIS (X-MEN: FIRST CLASS)

X-Men: First Class is the installment that almost single-handedly created the logical inconsistencies within the X-Men timeline. First Class uses the stories of young Xavier and Magneto to purposefully connect to the later movies, while at the same time nonchalantly retconning entire plot points. One such plot point is Xavier’s paralysis at the hands of Magneto. While the stray-bullet paralysis is shocking, there’s one little problem: An older Xavier was walking around just fine in X-Men Origins: Wolverine.

In the Wolverine movie, a younger and fully mobile Charles Xavier showed up in the finale. Yet in X-Men: First Class, which takes place 20 years earlier, an even younger Xavier is permanently paralyzed. The moment Charles is shot, it’s impossible not to flashback to his appearance in Origins and think “WHAT?” It’s such an important moment in Xavier’s development, and its direct contradiction of the previous film lessens the impact.

11 ROGUE'S POWERS RETURN (X-MEN: DAYS OF FUTURE PAST)

Days of Future Past featured the return of numerous old faces from the older X-Men movies. The publicity for the film included Anna Paquin as Rogue, though she didn’t show up in the theatrical version until the very end. The Rogue Cut Blu-Ray restored all of her scenes.

The pacing of the scenes don’t really work but there’s another glaring problem that presents itself the moment Rogue shows up -- she still has her powers.

In X-Men: The Last Stand, a cure was invented to suppress the X gene. Rogue took this cure, and it removed her powers “permanently.” Yet, when she shows up in DOFP, she’s so powerful that the sentinels have been holding her captive. Later, Rogue takes Kitty Pryde's powers to keep Logan in his past body. This is a glaring continuity error and it seemed that Bryan Singer wanted to pretend The Last Stand never happened.

10 LOGAN MEETS JEAN (X-MEN: APOCALYPSE)

Here’s an odd thing -- a continuity error in a sequel to a movie designed to rectify continuity errors. X-Men: Apocalypse features a feral Logan running into a young Jean Grey, who gently uses her powers to calm him. It’s a sweet scene, meant to hint at the relationship Jean and Logan would develop in the first three movies. There’s just one problem – those movies were wiped from continuity!

Days of Future Past made a huge stink about resetting the timeline, but we have no idea if the new timeline will include a future relationship between Logan and Jean. This tender Logan/Jean moment in Apocalypse is absolutely banking on your memory of their scenes in the first three X-films. Films that, according to Bryan Singer, no longer matter. Looks like Singer wanted to have his cake and eat it too.

9 SABRETOOTH'S DEATH (X-MEN)

The original X-Men featured a lot of great comic book-style fights. The final act contained a thrilling match-up between Wolverine and Sabretooth. There was one little problem though: at the end of the fight, Sabretooth was blasted into a watery grave by Cyclops.

Fans hoped for Sabretooth’s return, but he never came back in the present-day continuity.

This was one of the biggest mistakes in the X-Men series. There was so much potential for future stories involving Sabretooth and Wolverine but by killing him off in the first film, they effectively erased that potential. Granted, Tyler Mane was not exactly an inspired acting choice, and Liev Schreiber did a far better job in Origins. But Sabretooth’s early death prevented the possibility of Schreiber ever reprising the role beyond another prequel. Sabretooth’s demise was a clear case of short-sighted writers not seeing the character’s true potential.

8 LOGAN'S WEAKNESS (X-MEN ORIGINS: WOLVERINE)

Speaking of Sabretooth, X-Men: Origins features a ridiculously overpowered Victor Creed and a surprisingly weak Logan. In the comics, Sabretooth always had an advantage over Wolverine because of his heightened ferocity and looser morality, but Origins displays a discrepancy in power to the point of unbelievability. Sabretooth bests Logan again and again, breaking his claws and leaving him for dead. After Sabretooth kills Silver Fox, Logan volunteers for the adamantium procedure so that he’ll be strong enough to fight Sabretooth.

In the comics, Logan received the adamantium skeleton against his will after the Weapon X program plotted to manipulate his healing factor. Origins making Logan a willing participant ignores his iconic status as an independent-minded character. The notion that Logan decided he needed adamantium to fight Sabretooth makes him look weak. Logan’s strength is core to his nature and Origins’ depiction of Logan’s relationship with Sabretooth undermines that core strength.

7 MOIRA'S MEMORY (X-MEN: APOCALYPSE)

At the end of X-Men: First Class, Moira MacTaggert gets her memory erased by Charles Xavier. It was a weird moment which negated the impact of her character, and X-Men: Apocalypse tried to fix it. But instead of playing her memory loss seriously, Bryan Singer decided to turn Moira into a running joke. Throughout the movie she’s loopy and delirious, coming off more like an amnesiac patient than a telepath victim.

Moira was so strong in First Class, and in Apocalypse she’s a useless hindrance who needs to constantly be saved.

Rose Byrne plays Moira like she’s comic relief, and as a result, she feels like a completely different character. The fault lies with Singer, and Byrne/Moira deserved better. Luckily, Moira’s mind is restored at the end of the film. If Moira ever returns, this cringe-worthy version of the character will be nothing more than a memory.

6 XAVIER'S MIRACULOUS RETURN (THE WOLVERINE)

Xavier dies in X-Men: The Last Stand. Not only does he die, his body evaporates. Then, in the mid-credits scene of The Wolverine, he reappears out of nowhere. It’s a cool moment, and the reveal is meant to be jaw-dropping. But no explanation is given for Xavier’s re-materialization. Logan asks the professor “How is this possible?” and Xavier replies, “Like I once told you. You’re not the only one with gifts.”

Neither The Wolverine nor Days of Future Past offers a substantive answer. The most likely explanation is found in the director’s commentary on X-Men: The Last Stand. Brett Ratner reveals that Xavier’s consciousness latched onto the body of his twin brother, who was born brain dead. But three movies later, it’s no longer clear if Ratner's explanation remains true. The Wolverine has no interest in elaborating. Considering how impactful Xavier’s death was, his resurrection should have been equally meaningful.

5 WHO BUILT CEREBRO? (X-MEN: FIRST CLASS)

The identity of who built Cerebro is important in both X-Men and X-Men: First Class and the identity is completely different in both films. In the original flick, Xavier stated that Magneto helped him build Cerebro. This was relevant because it hinted at the friendship Charles and Eric once had. First Class tackles that early friendship, but for some reason depicts Beast building Cerebro. Meanwhile, Eric and Charles are both standing RIGHT THERE when Hank is explaining how he built it.

First Class is already built around Xavier and Magneto’s relationship, so why not enhance it through showing how they put aside their differences by building Cerebro together?

Building Cerebro would have been a great connective element back to the first film, and it would have enhanced the already strong emotional relationship between Charles and Eric in First Class.

4 MYSTIQUE AND STRYKER (X-MEN: APOCALYPSE)

At the end of X-Men: Days of Future Past, Mystique is seen fishing Logan from the water while posing as William Stryker. This opened up interesting possibilities for how Logan’s time in Weapon X might change, or if Logan would get his adamantium skeleton. Instead of exploring these possibilities, Singer elected to explore none. In X-Men: Apocalypse, Stryker is himself, and Mystique is the de facto leader of the X-Men.

This change likely derives from Jennifer Lawrence’s new status. It’s likely that Singer and his writers retconned their plans for Mystique in part because they wanted to capitalize on her stardom. This is a pretty poor excuse for such an egregious continuity error. It speaks to how Apocalypse overall prioritizes spectacle over story. It ultimately is not the kind of film that’s capable of playing with an idea as interesting as Mystique posing as Wolverine’s “Creator.”

3 THE DEATH OF CYCLOPS (X-MEN: THE LAST STAND)

Of all the stunning moves pulled by X-Men: The Last Stand, Cyclops’ death was by far the most offensive, mostly because it happens off-screen. The death is hinted at through broken glasses, yet the lack of a body leaves things inconclusive.

But he never returns, which forces us to the terrible conclusion that Cyclops insultingly died off-screen.

Cyclops’ death was just the cherry on top of a series of lackluster appearances. He was underused in both previous films, often coming off as an unlikable foil for Logan. The Last Stand unceremoniously kills Cyclops off in a movie that’s all about Jean Grey. It would have been the perfect opportunity for Cyclops to finally take center stage. Instead, Wolverine’s popularity meant he was given the role that Cyclops should have had. That’s why Cyclops takes the cake for most poorly treated character in the X-Men movie-verse.

2 "DEADPOOL" (X-MEN ORIGINS: WOLVERINE)

Need we say more? Ryan Reynolds' first appearance as the Merc with a Mouth took place in X-Men: Origins. Unfortunately the film’s finale that turns “Deadpool” into the single greatest laughingstock ever. When he shows up at the conclusion, he’s been altered into a freak mutant hybrid who looks more like Baraka from Mortal Kombat than Deadpool.

The mutilation of Deadpool was a huge slap in the face to fans. Instead of the comedic foil to Wolverine that he should have been, he became an all-powerful freak of nature. This silent abomination went against everything the clever, wise-cracking Deadpool stood for. Perhaps worst of all, this appearance totally wasted the talent of Ryan Reynolds. Luckily, Reynolds would eventually go on to star as the real Deadpool. But it’ll be a long while before the taste of Baraka-pool washes out of our mouths.

1 X-MEN: APOCALYPSE

X-Men: Apocalypse is the only entry in the series that totally fails to present interesting characters. It’s the only film in the X-series that feels like it’s trying to be a Marvel franchise rip-off. Apocalypse has no identity of its own, trying instead to set-up the next 10 X-Men movies with a new team and a generic, world-dominating villain.

X-Men: Apocalypse could have been so much more.

Magneto’s story arc involving the death of his wife and child is the best thing in the movie, but is ruined by the end. Apocalypse feels like it suddenly lost all ability to juggle multiple characters, with main characters like Mystique, Beast and Xavier relegated to paper-thin roles. By the time Singer got to Apocalypse, his creative spark had faded. It appears that Singer is now done with the X-franchise for good (or its done with him), and that’s probably for the best.