The Short Version:
While it contains thrilling action sequences and the patented Joss Whedon whit, it almost has too much of both while also being burdened with introducing and establishing new characters, giving time to the old characters, building up the threat of a new villain, AND still moving the MCU forward. The 3D is 100% completely worth the extra cash.
The Long Version:
I try to go into every movie I pay my $12 to see with as clean a slate as possible. I'll watch a trailer or two but I rarely read reviews prior to viewing. I just don't want expectations raised too high only to be let down. In the case of Joss Whedon's followup Avengers Age of Ultron I had hoped that I would be bombarded with some top notch action sequences and dialogue with a touch of creative banter and humor. What I got was entirely too much of both.
We greet our familiar heroes mid-mission as they are in all out assault mode attacking a secrete compound lead by evil German Hydra scientists. These scientists somehow managed to get ahold of Loki's scepter from the first film and have been using it do perform any number of evil experiments - none the least of which is human genetic manipulation in the form of Quicksilver (Aaron Tyler-Johnson) and his twin sister Scarlet Witch (Elizabeth Olsen). For a recap to you kids that don't read comics, Quicksilver can run really fast and Scarlet Witch has magnetic energy powers while also being able to do a little mind manipulation.
After the Avengers clear out the bad guys and reclaim the scepter, they go home the victors, have a party and relax for a few minutes. With the scepter in hand, Tony Stark AKA Iron Man (do I need to say played by Robert Downy Jr.?) and Bruce Banner AKA The Hulk (Mark Ruffalo) decide to play around with the mysterious energy source contained within the scepter. They quickly learn that it is in fact a form of intelligence. The intrepid scientists think "lets make artificial intelligence and we can save the entire world all at once!" So they start tinkering around and that doesn't exactly work out well.
By using Jarvis, Stark's electronic Butler as a roadmap, they inadvertently create Ultron. Designed and intended to be man's savior, the eccentric robot voiced by James Spader decides the world's best hope to survive is without the presence of man. rather than being a savior of the world, Ultron becomes a global threat taking control of robotics stations all over the world and embedding his consciousness in the internet allowing him to know all and see all instantly. Outmatched and outgunned, the Avengers must do their best to rally their strength, unlock Ultron's evil plot, and once again save the day.
Apparently there were several cut scenes and entire sequences that didn't make it into the final cut of the film - and it's noticeable. There is a late second act mission that Thor goes on in order to decipher the evil vision he had when he was infected by Scarlet Witch's mind control powers - only we get to see just a couple scant glimpses of what is going on and none of it makes any sense until some late and fast-worded exposition comes in. For an already long movie you can tell that this was intended to be an even longer film - for better or worse.
Part of the problem I have with this movie is that it opens headlong into an action sequence without reestablishing our characters. The last time we saw Captain America (Chris Evans) he was about to embark on some sort of mission with Falcon (Anthony Mackie) that sounded thrilling and exciting. We don't get to pick up with that. We get a long action sequence that easily could have been ten minutes shorter for how little it actually moves the plot forward.
Now don't get me wrong, I love action sequences and this movie delivers on that in a big way. But part of making an action sequence good or thrilling is making us care about the characters involved. One way Whedon tried to do that is by expanding on Hawkeye's (Jeremy Renner) character by giving him a family. On top of that we get Bruce Banner and Black Widow (Scarlett Johansson) building into some kind of romantic pair - which is weird because after Captain America: The Winter Soldier she clearly had eyes for the big boy in red white and blue, but so what, Johansson and Ruffalo play well off each other and their scenes are nice. The issue with these quiet character moments I have is that they grind the film to a screeching dead halt. Then when things need to get going again, the movie has to double clutch and grind its gears back into place before moving again.
With that, everything we watch for an hour and a half builds to a forty five minute climatic super battle that honestly, is straight out of the last movie only with mindless robots instead of mindless alien things. Our heroes protect the innocent while working towards taking down the main bad guy, Ultron. This would all be great if we hadn't seen it all already. After The Avengers and Man of Steel bad things falling from the sky can only be just so exciting for very long.
Now, how much of this is the fault of Writer/Director Joss Whedon? Really hard to say. Given his recent public behavior, the coy off-handed comments, and calling out other summer films like Jurassic World for supposed sexism while injecting a rape joke of his own is telling. I don't think he enjoyed this experience all that much. Maybe it's like he says and he's really burned out and his lips are a bit looser, but at the same time, it's entirely possible a lot of what he wanted to bring to the show was strangled by Disney/Marvel's need to keep the ever expanding franchise growing bigger and bigger. Where the Phase One line of films felt like they built towards The Avengers - this one feels like it's just a part of several stand-alone films that didn't really lead to this particular film in any real way other than a scattering of events from The Winter Soldier. On top of that - this movie feels entirely too "Whedon." We all know that he's a clever guy who knows where and how to throw out a smart quip, but he doesn't need to have EVERY character be quippy at all times. If Ultron had just been the only one, that would have been something - but even the most side characters, including random unneeded cameos from Agents of S.H.I.E.L.D. get a snarky quip. If there were good scenes left on the cutting room floor, I can guarantee that if they cut 90% of the unnecessary jokes out there would have been plenty of room for those scenes to come back.
That isn't to say Avengers: Age of Ultron is a bad movie. It is very fun and the action is often very thrilling. The Iron-Man / Hulk battle was fantastic - especially in 3D. Granted, I love 3D and am a bit biased, but this is a HUGE movie and it really makes use of the extra dimensional space. I loved James Spader's voice work for Ultron - he easily steals the entire movie. And, like the last Avengers movie, The Incredible Hulk is the best of the bunch. The big green monster gets all of the best fight scenes while also having a true and genuine emotional arc. That leads me to wonder why the hell they just don't make a new stand-alone Hulk movie again? One can hope.
In the end, I am more excited by the future single hero adventures coming up. This movie was a good bit of fun for a summer movie, it just wasn't nearly as memorable as the first Avengers film. Like I said it isn't a bad movie, I'll say I had a good time but not a great time - it's just average, and for a Marvel movie that's kind of tough medicine to take. I'm reserving final judgement for the Extended Cut thats rumored to arrive in the fall. It certainly isn't as bad as Iron Man 2 so that's something!
While problematic and overstuffed, Avengers: Age of Ultron was still a good bit of fun, it's just not as special as some of the more recent Marvel movies.