Contains *spoilers* - also, my quotes may not be exact.
Everyone always notes the satire in social commentary and economic parallels - how true. But to me, I see this movie as much more than that. I love the symbolism of this guy in a glowing white suit. There is so much confusion and filth in the world around him, but it won't stick. Alec Guiness was the perfect guy to play this - his boyish grins and eternal curiousity are so appropriate:
"That's ingenious - can you tell me, what is the ratio of ink to petrol?"
The only moment of defeat is when he realizes that his invention hasn't worked after all - standing there almost naked. Yet, more than shame is the simple disappointment that "it didn't work." He's never really intimidated by people. Remember,
"But Sidney, we want to stop it too."
Barely a moments hesitation before he's off trying to get away again. Does he show any sign of the pain such a betrayal must've caused? No.
Also notable is Dapne's role. She is sick and tired of money and power. She thinks she's finally found love, outside of her father's company. At first she doesn't really care about Sidney anymore than anyone else. But that moment when he falls off her car and she goes back to see if maybe she killed him - and yet he is still thinking only of the beauty of his invention. She's finally found something she thinks is worth living for. The funny thing is that it's not even romance. It is friendship, but of such an ephemeral nature that the title almost doesn't fit. It's more admiration, and perhaps even inspiration.
Upon her discovery that Michael has no real love for her, and that her father is completely incompetent to take care of her, she gives into cynicism and tries to temp Sidney. Fortunately she finds that there really are people in this world living for more than power, money and lust. What a refreshment:
"Thank you Sidney. If you would've said 'yes' I think I'd have strangled you."
I love the very end, when all of this crazy business seems to have come to nothing. But then, the bubbly, quirky beat starts up and Sidney goes off, his stride matching the tune: dauntless. Where is Daphne? We don't really know - but they weren't really in love and she wasn't really a scientist. He got help escaping and she got "a shot in the arm of hope." (Pollyanna) A cont'd relationship would've been nice, but as Billy Joel says "it's more than I'd hoped for..."

Who are these "They"- the actors? the filmmakers? Certainly couldn't be the audience- this is among the most air-puffed productions in existence. It's the kind of movie that looks like it was a lot of fun to shoot TOO much fun, nobody is getting any actual work done, and that almost always makes for a movie that's no fun to watch.
Ritter dons glasses so as to hammer home his character's status as a sort of doppleganger of the bespectacled Bogdanovich; the scenes with the breezy Ms. Stratten are sweet, but have an embarrassing, look-guys-I'm-dating-the-prom-queen feel to them. Ben Gazzara sports his usual cat's-got-canary grin in a futile attempt to elevate the meager plot, which requires him to pursue Audrey Hepburn with all the interest of a narcoleptic at an insomnia clinic. In the meantime, the budding couple's respective children (nepotism alert: Bogdanovich's daughters) spew cute and pick up some fairly disturbing pointers on 'love' while observing their parents. (Ms. Hepburn, drawing on her dignity, manages to rise above the proceedings- but she has the monumental challenge of playing herself, ostensibly.) Everybody looks great, but so what? It's a movie and we can expect that much, if that's what you're looking for you'd be better off picking up a copy of Vogue.
Oh- and it has to be mentioned that Colleen Camp thoroughly annoys, even apart from her singing, which, while competent, is wholly unconvincing... the country and western numbers are woefully mismatched with the standards on the soundtrack. Surely this is NOT what Gershwin (who wrote the song from which the movie's title is derived) had in mind; his stage musicals of the 20's may have been slight, but at least they were long on charm. "They All Laughed" tries to coast on its good intentions, but nobody- least of all Peter Bogdanovich - has the good sense to put on the brakes.
Due in no small part to the tragic death of Dorothy Stratten, this movie has a special place in the heart of Mr. Bogdanovich- he even bought it back from its producers, then distributed it on his own and went bankrupt when it didn't prove popular. His rise and fall is among the more sympathetic and tragic of Hollywood stories, so there's no joy in criticizing the film... there _is_ real emotional investment in Ms. Stratten's scenes. But "Laughed" is a faint echo of "The Last Picture Show", "Paper Moon" or "What's Up, Doc"- following "Daisy Miller" and "At Long Last Love", it was a thundering confirmation of the phase from which P.B. has never emerged.
All in all, though, the movie is harmless, only a waste of rental. I want to watch people having a good time, I'll go to the park on a sunny day. For filmic expressions of joy and love, I'll stick to Ernest Lubitsch and Jaques Demy...