Avengers, Assemble! Or, you know, don’t. In a recent interview with Empire Magazine about Marvel’s most recent blockbuster, Avengers: Age of Ultron, director Joss Whedon explained his deliberate avoidance of one of the most iconic lines in comic book history at the close of the film: “I made sure that we never shot Chris Evans [Captain America] saying ‘Assemble!’” Whedon said. “I was positive that some executive was gonna go, ‘You forgot to put in the last word!’ I was like, ‘With my dying breath…’ I don’t have to say that a lot, but sometimes I’ll turn to [Marvel President] Kevin [Feige] and say, ‘With my dying breath… ”

Just before blackout, Evans sizes up his teammates and calls “Avengers —” and the film ends, just like that. This ending is perhaps one of the most dissatisfying for Marvel fans and newcomers to the franchise alike; the former falling off the edge of their seats waiting for that one word, while the latter scratch their heads in mystified curiosity.

This deliberate refusal to acknowledge essential comic book lore is the major flaw in an otherwise enjoyable movie. Sure, Whedon wants to separate the cinematic universe from the comic universe, but this sort of casual disregard damages the already massively overstretched suspension of disbelief that accompanies a Marvel film.

Consider the titular character Ultron, played by James Spader. The living automaton Ultron-5 first appeared in 1968. Writer Roy Thomas slowly revealed his complex origin throughout the next several years. Here’s the main kicker: Ultron cannot die. Over the past 50 years, the android has been repeatedly smashed, blown to bits, melted and cast into the farthest reaches of time and space. But he always comes back.

In the comics, Ultron’s brain is modeled on that of the scientist Hank Pym, also known as Ant Man; in the film, it’s modeled on Tony Stark, also known as Iron Man. In the latter case, his motivation for the traditional “destroy the world” rigmarole is never fully fleshed out. His only interactions with his creator involve entertaining but unsatisfactory fisticuffs, never resolving the issues of his demented sapience. Unlike Loki, whose development as a character prior to and during the first Avengers film gave the heroes something genuinely sinister to battle against, Ultron’s rushed development and off-screen destruction at the film’s conclusion never seem to pose a serious threat to humanity; Whedon never articulates why he is such a malevolent robot.

Similarly, the two new kids on the block, the twins Pietro and Wanda Maximoff — Aaron Taylor-Johnson and Elizabeth Olsen, respectively — come across as haphazardly thrown together. Despite repeated expositional material, their characters never quite seem to fit in. Perhaps they’d be more at home in an X-Men film, where, based on Marvel’s history, they belong.
 With botched Eastern-European accents, the Maximoffs add little to the film except an excuse for additional special effects. Hawkeye, played by Jeremy Renner, delivers a far more gratifying character arc. Renner’s confident delivery helps to ground a film otherwise predicated on the sleight of hand. If only viewers would forget about plot holes when fed crazy battle sequences. Hawkeye does ultimately lend stability to Age of Ultron through his developing relationship with the team as “the normal guy.”

This is Chris Evans’s fourth portrayal of Captain America. He has the Boy Scout routine down pat, and his interactions with the more worldly characters provide an abundance of comic relief. Robert Downey Jr., Chris Hemsworth and Scarlett Johansson — Iron Man, Thor and the Black Widow, respectively — have also mastered their characters after multiple appearances. The real draw to this film is flippant dialogue, lightly tossed off between the teammates, regardless of the chaos going on around them. Whedon captures the frivolity of the comics well, ensuring that the characters never take themselves too seriously — except for when they do.

Mark Ruffalo’s Hulk, whose CGI marks one of the few improvements on the first film, continues in his dramatic quest to avoid accidentally harming innocent people. In Age of Ultron, however, his bizarre romance with Johansson’s character adds an additional “Where did that come from?!” moment in a movie already overstuffed with clunky exposition.

Despite a jerky narrative arc, one thing this film does do extremely well is set up the next big Marvel event: Civil War. Evans and Downey Jr. do an excellent job portraying their characters’ mounting frustrations with each other’s approaches to world security, making it easy to predict the showdown supposedly coming in the next Captain America film.

Is Age of Ultron as good as the first Avengers? No. But it’s still a good film. Although riddled with a disappointing lack of character development — which was probably the first film’s secret — Whedon maintains the light humor and fast pace with consistency. And the battles are beautiful: heavily choreographed and way over the top in some cases but comic bookworthy beautiful. Age of Ultron is certainly worth watching, just be prepared for some mild confusion along the way.