First, Stephen Hunter in the Washington Post:
In “The Simpsons Movie,” no good deed goes uncrushed.
This merry celebration of mayhem, hostility, carnage, wanton destruction, power lust, dysfunction, nihilism and the proper application of gigantic plastic domes to American cities will certainly satisfy those who’ve seen all 400-odd episodes of the TV show twice, as well as those who’ve only glimpsed the Simpsons on a transmigration to more sports programming. Happily, it’s full of things that are bad, but in a good way
(…)
The genius, then, is in the writing and in the writing supervision — the overall editorial view in which all gambits created by individual writers are kept in sync, so the piece has a tonal consistency and narrative flow. A lost art in Hollywood? I wouldn’t want to say, but it was something severely lacking in, say, something like “License to Wed.”
Some “Simpsons” lifers may miss the prominence of certain favored characters. Apu, the convenience store manager, doesn’t get much screen time. Neither does the misanthropic C. Montgomery Burns, who only gets to sic his dogs on the peasants once. Krusty the Clown has a little more time and maybe Ned Flanders (the mellow next-door neighbor who’s an idealized dad) gets a little too much.
It’s really one of the best movies of the year.
Then, from The New York Times:
I have long been of the opinion that the entire history of American popular culture — maybe even of Western civilization — amounts to little more than a long prelude to “The Simpsons.” I don’t think I’m alone in this belief. But it does not follow that “The Simpsons Movie” represents a creative peak toward which the show’s 18 seasons and 400 episodes have been a long, slow climb. Let’s keep things in perspective. “The Simpsons” is an inexhaustible repository of humor, invention and insight, an achievement without precedent or peer in the history of broadcast television, perhaps the purest distillation of our glories and failings as a nation ever conceived. “The Simpsons Movie” is, well, a movie.
(…)
Ten or 15 years ago, “The Simpsons Movie,” which has been contemplated for almost as long as the show has been on the air, might have felt riskier and wilder. But “The Simpsons,” for all its mischief and iconoclasm, has become an institution, and that status has kept this film from taking too many chances. Why mess with the formula when you can extend the brand? Do I sound disappointed? I’m not, really. Or only a little. “The Simpsons Movie,” in the end, is as good as an average episode of “The Simpsons.” In other words, I’d be willing to watch it only — excuse me while I crunch some numbers here — 20 or 30 more times.
Sounds like it will fun.

