In short: Wes Anderson being Wes Anderson (just like with The Royal Tenenbaums, The Life Aquatic with Steve Zissou and Fantastic Mr Fox).
Moonrise Kingdom is the story of two young children who run away together on a small New England Island in the 60s, and how the community around them deals with it. It's typical Anderson territory: a comedic drama with a lot of innocence and whimsy on the surface, doing a not so good job of hiding the more depressing things going on in the background. He's very much the inversion of Tim Burton. Burton's films are typically dark affairs with stark contrasting colours that are visually quite dark and gothic but thematically are uplifting and positive. Then you get Anderson's warm, subdued palettes covered in yellows, tans and pastel reds and blues within childlike characters with deep seated issues.
Moonrise Kingdom is very much an ensemble cast. At the centre are the surprisingly talented Jared Gilman and Kara Hayward as the runaway couple. Honestly, I usually hate child actors because they're (understandably) shit, but Gilman and Hayward here are easily on par with Natalie Portman in Leon and Chloë Moretz in Kick Ass. They're surrounded by talent too, though. Edward Norton (who still doesn't seem to have aged since Fight Club) and Bruce Willis are charged with the operation to find the kids in their respective roles as Sam's Scout Leader and the island's police chief. Both are fantastic in their similar characters, both are downtrodden men with happily mundane lives who are hit hard by Sam's disappearance, as well as revelations about the boy's situation. As with the last six Anderson productions, Bill Murray makes an appearance too, as the girl's frustrated and angry father who's trapped in a rut with his wife and kids.
At it's heart, the film is a love story. Considering the ages of the characters though, it's difficult to come down and say if it's childlike or not though. There's all the "seriousness" that kids who think they're in love have, but there are some moments where some real maturity shines through and often leaves you questioning who it is that really has their head on right, the kids or the adults? A number of sub plots, including a ragtag bunch of scouts channelling a 50s biker gang, a cheating wife and a physical embodiment of Social Services, all add to the whimsy and charm of the film as a whole.
A special note should be made of the excellent soundtrack (showcased pretty well in the trailer, below). It lends the film a certain feel of adventure, while still instilling an air of safety that runaway kids these days would most definitely not have.
Moonrise Kingdom might not be Wes Anderson's best film (that honour blatantly goes to Fantastic Mr Fox. George Clooney as a charming animated fox, what could be better?) but it's certainly a great watch and a beautifully crafted, funny and touching film. But watch FMF as well.Seriously, it's amazing.