Joss Whedon has been a nerd-culture messiah since “Buffy the Vampire Slayer,” but his recent treatment of the Avengers has begun turning him less messiah and more pariah.

The newest addition to the Marvel Cinematic Universe (MCU), “Avengers: Age of Ultron,” is leaving a sour taste in comic book fans’ mouths and even more casual fans, like myself, are sensing something rotten in the Avengers Tower. From completely off-the-wall characterization of just about every Avenger to the whitewashing of the Maximoff twins (Quicksilver and Scarlet Witch), “Ultron” reads as a mess of a fanfiction, not a serious movie.

Whedon’s trademark style of quippy one-liners may work well in “Firefly” and “Buffy the Vampire Slayer,” but when he does the same in “Age of Ultron,” it is difficult to get a solid tone on the movie. Is it serious? Is it fun? With just about every scene giving the audience whiplash by going from Ultron talking about people creating their fears to making some half-baked joke about people being scared of babies, it’s downright impossible to maintain any actual fear or sense of danger. In fact, if I didn’t know Whedon had written “Age of Ultron” himself, I would have guessed it was some Whedon fan attempting to mimic his style and going too far over the edge.

The sloppy characterization of Ultron isn’t limited to this new character, but infects all the characters we’ve come to love over the last seven years. Steve Rogers, an orphan from Brooklyn who later became a soldier, is once again apparently some hyper-moralistic, anti-swearing 90 year old, and Natasha Romanov’s entire character gets thrown out the window in favor of an ill-advised, will-they-won’t-they back and forth with Bruce Banner. Even Tony Stark, Whedon’s obvious favorite character, has most of his depth stripped in favor of his witty banter.

Romanov is given one line strictly about herself in the whole movie, which is used to say, point-blank, that her forced sterilization at the Red Room made her a monster, in order to relate better to Banner’s typical sulking over being the Hulk. Aside from being unbelievably offensive to people who have undergone both voluntary and forced sterilization, as well as people who are sterile due to biological issues, it seems completely unlike Romanov to consider herself a monster for being unable to bear children.

The choice to even include the Maximoff twins is confusing, since the “X-Men” franchise is owned by Sony and therefore can’t even be mentioned in the MCU. So the twins, rather than being mutants, are referred to as “enhanced” and were made that way by Dr. Stoker — a German scientist with Hydra. The Maxinoff twins are canonically, in the comics, Romani Jews. Whedon not only stripped them of their religion and race, but he specifically had them volunteer to be experimented on by a Nazi organization. Since mutants and X-Men don’t exist in the MCU, it makes sense he would have to construct a new backstory for them, but why even bother including mutant characters if you have to restructure almost their entire backstory? It’s honestly baffling.

All of that being said, for people who have no interest in the comics or who are simply looking for a fun, brainless, superhero action movie — “Avengers: Age of Ultron” fits the bill. It’s action-packed and not too cerebral, and honestly, it’s a summer blockbuster. It does what it sets out to do as a form of entertainment, it’s just not a Marvel movie as far as I’m concerned.

But hey, at least Hawkeye actually manages some significant screen time.