The year is "the future" and giant monsters - Kaiju - are steadily emerging from a rift deep under the Pacific Ocean, laying waste to coastal cities and killing thousands. To combat them, giant robot - Jaegars - have been created, piloted by two pilots under a mental link - the Drift - and after initial success are now being steadily defeated, leaving humanity with only one final, desperate chance. Its main characters are a burnt-out veteran, a rookie, a dueling father-son team, a pair of bickering scientists and noble, self-sacrificing commander. And that's pretty much all you need to know about the story.
Now usually I'd be saying "weak story, basic characters", but Pacific Rim is a great example of cinematic shorthand. At heart, its not a film confused about what it wants to be, or what it wants to show. Its very clear: this is a movie about massive fights between robots and alien lizard-monsters the size of skyscrapers, and everything is build about giving these fights as much weight as possible, in as fast a time as possible. So the characters are easy to get a handle on because Del Toro wants you to care about them, and fast, and the familiarity makes that easier. The story is straightforward so you can invest in the stakes quickly and easily. All it asks for the initial buy-in and it rolls you along from there.
I've been a fair few of the big films this year and they can pretty uniformly be described as "I enjoyed that, but....". If only Star Trek Into Darkness had a plot that made any sense. If only Man of Steel had been able to bring its more interesting character themes together in its final act. There isn't any "but..." with Pacific Rim, it's simplicity is turned to a virtue, it's spectacle as long as it needs to be. It knows its a Giant Monster movie, it knows it's selling spectacle, and really that all it wants to do, as well as it can. And critically, it succeeds.
The fights are truely massive; well scripted, clear and (rarely these days!) not repetitive. The Jaegars have tons of personality (more, perhaps than their pilots) and manage to pull out new moves and weapons as the film goes on without feeling too contrived, and usually for maximum "Hell, Yeah!" effect. It's also gloriously internationalist - its centre piece is set in Hong Kong, the Jaegars come from around the Pacific, and the central theme is of humanity coming together to overcome adversity, stronger together, rather than the paeans to exceptionalist individuality that we're used to from the superhero genre.
If I had to pick niggles, I could have done with at least one more female character, and I would like to have seen more of the Russian and Chinese Jaegers. Its a credit to the design of the whole movie - little details, more shorthand - that it fleshes out the world in the background and leaves you wanting more of it. It's clearly a labour of love and tribute to a genre of movie that has never gained more than a cult following in the West.
In the final analysis, I'm not sure that Pacific Rim is going to start to redefine the summer blockbuster, and its merely adequate opening weekend in the US means it will look internationally to make its money, although I suspect that it will fine on that front. It's not really doing anything hugely new, either, but it is doing it extremely well, and in the summer of "yes, but...", I feel it deserves some recognition.