You know how people always say that a movie with giant robots in it is awesome by definition? This is the first movie I've ever seen where I can honestly say that's true.
Pacific Rim is...a mixed bag of a movie. To be perfectly frank, most of the non-action scenes really aren't that good. The actors do their best (most of them anyway) but the plot is razor-thin and the script is pretty mediocre. In fact in some places it's pretty damn bad.
But, BUT, the actions scenes are SO good that you'll barely notice.
Brief plot summary (spoilers):
Aliens from another dimension open a portal to our Earth (the portal comes out at the bottom of the Pacific ocean, hence the title) and start sending giant monsters through to wipe out humanity. Why giant monsters? WHY NOT?
Conventional weapons prove useless against the monsters so the nations of Earth instead decide to fight the monsters with giant robots. Why giant robots? WHY NOT?
This works out for a while, but eventually the giant robots start losing more fights than they win and the governments of the world decide to scrap the giant robot plan and instead build a giant wall to keep the giant monsters out. Why a giant wall? WHY N-...actually I have no idea why they think this will work. I guess they think the monsters will see the wall and be like "Well, shit. They built a big fuck-off wall. Might as well go home."
Of course the wall completely fails (surprise!) so they go back to the giant robot plan. They call the main character out of retirement and pair him up with a hot Japanese chick to pilot his giant robot again. Oh yeah, I forgot to mention the giant robots are piloted by two people at once. The two pilots link their brains together and move as one. I don't know why they wrote the movie this way. It's a contrived and unnecessary detail that adds nothing to the movie. They should have given each pilot their own giant robot to drive around. They could have even kept the brain-linking plot point, just have them linked wirelessly and fighting in tandem. Then you have twice the giant robots. How is this a bad plan?
Anyway, they figure out that the aliens are going to keep sending more and more monsters until it overwhelms them and wipes out humanity, so they decide to send their giant robots down to the bottom of the ocean and drop a big nuclear bomb through the portal to wipe the aliens out first. Why a big nuclear bomb? WHY NOT?
So of course they head down there and fight a couple more giant monsters, a couple other giant robot pilots make a heroic sacrifice, they drop the big bomb down through the portal and the world is saved.
(end summary)
All in all, I liked this movie. Not a lot, but enough that I'm glad I saw it and I feel I got my money's worth. As others have said, it's basically a huge love letter to Japanese giant monster movies and giant robot animes. And fuck me, when it comes to the giant monsters and giant robots they actually got it right. The simple fact that they didn't fuck it up is a not-insignificant accomplishment. This could so easily have gone terribly wrong, but it didn't. And I think we have Guillermo del Toro to thank for that. Whatever else you might say about Guillermo del Toro, the man GETS giant robot and giant monster movies. He understands probably better than any other person in Hollywood what makes a good giant [thing] movie. The movie isn't perfect. Basically any scene without a giant robot or giant monster in it stinks out loud. And I don't mean bad like "why are we watching this instead of watching giant robots fighting giant monsters?" I mean they are objectively bad. Sometimes painful to watch, even. But the fight scenes are good enough to make you not care too much.
Also, there's something else that jumped right out at me. Something I haven't seen any other reviewer comment on. The romance subplot. Or the total lack thereof. There is no romance subplot in this movie. That shocked the shit out of me. There was every opportunity to have a romance subplot. Handsome male lead gets paired up with hot young Japanese chick to pilot giant robot. They've got stuff in common, they work well together, Hell they've been inside each other (that is, they've been in each other's brains). As soon as this woman showed up I thought "Well, crap. We all know where this is going. Get ready for lots of tired, unnecessary scenes rehashing every movie romance cliche imaginable."
And yet...NOT ONCE do they hook up. They don't even kiss. I waited the whole movie expecting another tedious romance subplot and it never happened. Hallelujah.