Gravity is the single most thrilling experience I've ever had in a movie theatre. It's not particularly deep. It doesn't have a lot to say. But everything it does it does so well, so flawlessly and immersively... the closest comparison I can make is to how I felt seeing Jurassic Park in the theatre as a kid during the T-Rex scene. You know the Rex is coming, and Spielberg lets that dread build and then we get the big reveal and it's intense and scary and perfectly executed.
The big bad in Gravity isn't an animal, it's a cloud of shrapnel flying around the earth at 50,000 miles an hour, and every time a main character is spacewalking, that same feeling of dread overwhelmed me, and those big moments... they're shot unlike anything you've ever seen. They're terrifying and visceral and had me going "ohshitohshitohshit" in the theatre... they're relentless.
The movie does provide moments to breathe in between the mayhem. You'll need them.
The central theme of the movie is around adversity and rebirth - not anything especially groundbreaking, but I found myself really rooting for the characters to survive and make it home. It's a credit to both George Clooney and Sandra Bullock that their characters are believable and sympathetic despite their flaws. There's a moment in the film where a character has a moment of doubt and I wanted to scream at the screen for them not to give up. That's not something that usually happens with me, but whatever magic Alfonso Cuaron weaved to immerse me in the story worked. Hard.
There's a plot point that's a little Deus Ex Machina-ish, which threw me a little... but it provided a necessary piece of character development, so even that isn't too bothersome.
Gravity comes out next month. You owe it to yourself to see it in the biggest, loudest theatre you can find, with a massive crowd.
I'd also recommend avoiding the trailers that have come out since the initial teaser trailer I've embedded above. There's moments hinted at in the later trailers that I never saw coming (since I deliberately skipped them) that will only make the in-theatre experience that much better. Trust me. You'll love it.