The Spoilers: As a doctor helpfully tells Matt Damon - twice! - "your wife is dead." So Gwyneth is the monkey, then.
How They Should've Sold It: You'd think in a film with so many stars they'd be able to draw attention away from Gwyneth's fate. Why give the bit-part doctor any trailer time at all?
Free Willy (1993)
The Spoilers: "If we don't get him into water soon, he's gonna die!" How about we get him into the ocean before the trailer ends?
How They Should've Sold It: End the trailer on the possibility that Willy might die… although that would risk replacing the family audience with a niche demographic of whale-haters.
The Spoilers: Voiceover guy tells the entire story, even down to explaining that "she'll be voted Queen of the Prom" - cut to splattering pig's blood and split-screen carnage.
How They Should've Sold It: Play up the mystery as to what's different about Carrie. Which means dropping the shot where she looks up 'telekinesis' in the dictionary.
The Lord Of The Rings: The Two Towers (2002)
The Spoilers: Who's this White Wizard that everybody's so interested in? Oh, it's Gandalf. Yes, that Gandalf. The one we thought had died in the last movie.
How They Should've Sold It: There's a whole hour's worth of battle footage they could have used without giving away too much.
The Island (2005)
The Spoilers: Steve Buscemi blows the entire plot by telling Ewan McGregor, "You're not real," you're copies of people out here in the world."
How They Should've Sold It: It's a Michael Bay film. Blow something up.
The Spoilers: Sean Bean's the baddie. Which is great until you see the film and discover he supposedly 'dies' in the pre-credit sequence.
How They Should've Sold It: It was the first 007 film in six years. Just play the theme, show some action, end on a quip. Leave the plot details alone.
Charlie's Angels: Full Throttle (2003)
The Spoilers: Demi Moore's the baddie. Fair enough, until you see the film and realise that's supposed to be a twist.
How They Should've Sold It: Again, plot's not exactly top of the agenda for this film's target audience. Stick to the cleavage and kickboxing.
Double Jeopardy (1999)
The Spoilers: Ashley Judd is locked up for killing her hubby, but when she discovers he's still alive, the plot is helpfully spelled out: "Ever hear of double jeopardy? That means when you leave here, you can kill him and there's nothing anybody can do about it."
How They Should've Sold It: It's not exactly the most challenging of plotlines to guess, but at least stripping away the exposition would make us work a bit harder.
Terminator Salvation (2009)
The Spoilers: Who's the mystery man played by Sam Worthington? Oh, he's a Terminator.
How They Should've Sold It: There's no real reason to show Worthington at all. Concentrate on the cybernetic action and Christian Bale's John Connor.
Arlington Road (1998)
The Spoilers: Is Jeff Bridges crazy, or is his new neighbour Tim Robbins a terrorist? Watch the film to find out... or, you know, watch the trailer.
How They Should've Sold It: Actually, this comes perilously close to giving away the ending, too, so maybe they'd have been best to caption Robbins' screen-time with "Yes, he is a terrorist" in order to bamboozle us.
Cast Away (2000)
The Spoilers: Reckon Tom Hanks gets off the island? "You were lost for four years," his mate tells him. So, yeah, he probably makes it.
How They Should've Sold It: Remove any footage from the film's final fifteen minutes. It isn't rocket science.
What Lies Beneath (2000)
The Spoilers: Michelle Pfeiffer investigates what she thinks is the ghost of a neighbour. Lucky the trailer is here to explain that, really, it's the woman that hubby Harrison Ford had an affair with.
How They Should've Sold It: Robert Zemeckis sure didn't give a monkey's about spoiling his movies in 2000. Maybe he should've hired a more discreet trailer editor.
Funny People (2009)
The Spoilers: "We may have beaten this thing." Clearly, the prospect of Adam Sandler dying is too much to bear.
How They Should've Sold It: A ratio of one-quarter 'illness melodrama' to three-quarters chuckles. C'mon, the Adam Sandler audience isn't that discriminating.
Star Trek III: The Search For Spock (1984)
The Spoilers: Holy shit, the Enterprise has been destroyed! Now imagine how much more of a shock that would have been if they'd saved it until midway through the film.
How They Should've Sold It: Bizarrely, this trailer ignores the whole premise of the film, so some footage of Kirk and co. searching for Spock would be nice.
Pirates Of The Caribbean: At World's End (2007)
The Spoilers: A bit of a subtle one, but the shot of Orlando Bloom at the helm of the Flying Dutchman with a massive sword wound on his chest is there to see.
How They Should've Sold It: Be honest, people are only interested in Johnny Depp as Jack Sparrow. Orlando doesn't need a hero shot.
Dream House (2011)
The Spoilers: OK, so the clue's in the title, but does the trailer have to spell it out so clearly that Daniel Craig's life with Rachel Weisz isn't real?
How They Should've Sold It: By playing down the story's shifting realities and marketing it as a straight-down-the-line haunted house chiller.
The Negotiator (1998)
The Spoilers: Jackson vs Spacey? Hell yeah... Until Spacey says, "Now you're gonna have to deal with both of us," and reveals they end up working together.
How They Should've Sold It: Simple. Jackson vs Spacey.
From Dusk Till Dawn (1996)
The Spoilers: Ooh, that's a cool looking crime thriller. Oh, hang on, it's a cool looking vampire thriller.
How They Should've Sold It: Use the trailer to tease the mid-film genre rug-pull, so that everybody thinks they're watching a cool looking crime thriller until the dying seconds of the trailer.
The Spoilers: A typically sly Hitchcock trailer with specially shot material gives away to a spoilerific recap of the film's last act.
How They Should've Sold It: Do the whole trailer straight-to-camera and dispense with any footage from the film.
The Last House On The Left (2009)
The Spoilers: The entire film, right down to how chief villain Garret Dillahunt is dispatched. Presumably, the makers figured audiences would pay simply for the rape and revenge.
How They Should've Sold It: End on a cliffhanger as the parents discover who their new house guests are.
Fantastic Four: Rise Of The Silver Surfer (2007)
The Spoilers: Having established that the Fantastic Four can swap powers, the trailer proceeds to show the climax where the Human Torch has all of their powers.
How They Should've Sold It: Isn't it enough to have four superheroes fighting a silvery surf-dude from space?
Grosse Pointe Blank (1997)
The Spoilers: Everything, up to the big reveal that John Cusack's latest target is the dad of childhood sweetheart Minnie Driver.
How They Should've Sold It: This one's just baffling. It virtually ignores the film's impressive second act set-pieces in its rush to ruin the climax. Perhaps, just maybe, the emphasis should be the other way around?
Hot Tub Time Machine (2010)
The Spoilers: Time traveller Clark Duke sees his young-again mom. Mate Rob Corddry pulls her. She lies in bed, saying "I feel pregnant." Join the dots.
How They Should've Sold It: By removing at least two of the dots. There's more than enough crowd-pleasing 1980s nostalgia to entertain us without going all timey-wimey.
The Sum Of All Fears (2002)
The Spoilers: "They're building a bomb." Fair enough. The bomb goes off? Bang goes the film's tension.
How They Should've Sold It: End on a countdown. The audience will assume Ben Affleck stops the bomb and will therefore be almightily shocked when they see the film.
Children Of Men (2006)
The Spoilers: In a world without hope, where women can no longer have babies... that pregnant belly is one helluva spoiler.
How They Should've Sold It: Arguably, this is a case where one spoiler is sacrificed to protect another (sssh!) but the way Cuaron shoots action means there's plenty of other footage that could have been used.
Death Proof (2007)
The Spoilers: True to the spirit of the grindhouse classics, Quentin Tarantino's car-smash homage simply plays the film out sequence-by-sequence.
How They Should've Sold It: Try chopping up the order of events. It worked for Pulp Fiction .
Spider-man 3 (2007)
The Spoilers: So many subplots and villains to choose from... so why not throw them all into the mix?
How They Should've Sold It: It's actually a fairly accurate depiction of the bloated final product, so maybe this is a case where the film needed streamlining first.
Final Destination 5 (2011)
The Spoilers: Continuing a franchise tradition, this gives away every death, give or take.
How They Should've Sold It: Five films, and millions of dollars later, we suspect nobody cares.
The Spoilers: Another sprawling 1970s trailer that feels no compunction about showing chunks of the final scene, right down to "Forget it, Jake, it's Chinatown."
How They Should've Sold It: By steering clear of the final act in favour of more hats, cars, fights and Jack Nicholson in his prime.
The Incredible Hulk (2008)
The Spoilers: The trailer's entire second half shows the Hulk's climactic showdown with Abomination. And don't get us started on later edits that show the post-credits cameo by Tony Stark.
How They Should've Sold It: An alternative cut gets it bang on by emphasising Edward Norton's flight from the authorities and only hinting at Tim Roth's transformation.
Twilight: New Moon (2009)
The Spoilers: The Reader's Digest version. It shows so much it spares any need to actually watch the film.
How They Should've Sold It: By remembering that a trailer implies leaving a trail to follow, instead of presenting the whole plot on a Sat Nav.
When A Stranger Calls (2006)
The Spoilers: There's a stranger trying to break in! Oh, hang on: "We've traced the call, it's coming from inside the house."
How They Should've Sold It: There's a stranger trying to break in! Just that.
The Dark Knight (2008)
The Spoilers: Gary Oldman's Commissioner Gordon is seen ushering the Joker into a prison cell and smashing the Batsignal. Both of which events happen after his supposed death in the film.
How They Should've Sold It: We love Gary Oldman, but it's fair to say there's a decent excuse here to downplay his involvement. With Bale, Ledger, Caine, Freeman and the rest involved, it's not as if there's a shortage of star power.
Total Recall (1990)
The Spoilers: Arnie's female disguise, his false memories, "Consider that a divorce!" Pretty much the whole thing bar the triple-breasted whore, then.
How They Should've Sold It: Ah, the eternal perils of trying to make a cerebral action-flick. Too much talk, and the Schwarzenegger fanbase bails. But cut to the chase, and it kinda gives the game away.
The Curious Case Of Benjamin Button (2008)
The Spoilers: Presumably, the editors got so confused by Brad Pitt's reverse ageing that they figured it wouldn't matter if they sped through the whole plot.
How They Should've Sold It: Backwards. That'd really be messing.
The Spoilers: Tobey Maguire went to war and died. So now bro Jake Gyllenhaal can get it on with widow Natalie Portman. Except Tobey Maguire didn't die.
How They Should've Sold It: It's probably impossible to keep this secret without making the film look really boring, but a bit of subtlety wouldn't have gone amiss.
The Spoilers: "You're going up against gunships with bows and arrows!" No need for two hours of preamble, then.
How They Should've Sold It: Monsters, spaceships, giant smurfs.
The Spoilers: It takes two minutes to figure out that William H. Macy is running a sex slave business. The film takes about an hour and a half to reach that point.
How They Should've Sold It: With the emphasis on director David Mamet's trademark terse dialogue and knotty plotting. Presumably they figured that, without action, the film would look a bit… well, spartan.
Home Alone (1990)
The Spoilers: Christmas came early, when this Jingle Bells-themed ad showed pretty much every trap that Macauley Culkin leaves for the robbers.
How They Should've Sold It: To be fair, this one's funny enough to forgive.
National Treasure: Book Of Secrets (2007)
The Spoilers: Nic Cage goes on a treasure hunt across the world looking for the President's big book of secrets. A quick glance at the trailer would have made its location obvious.
How They Should've Sold It: With a few judicious trims, this one would be fine. It's as if Hollywood trailer editors can't look at footage of a famous monument without bunging it in.
The Spoilers: "Don't let anybody tell you what it is." Trouble is, this trailer gives away the twist that Nev Schulman's Facebook girlfriend might not be all she seems.
How They Should've Sold It: A tricky one. Catfish is one of those films where knowing anything is a disadvantage. At least the trailer has the decency to stop before revealing who she really is.
Soylent Green (1973)
The Spoilers: "What is the secret of Soylent Green?" This three-and-a-half minute long trailer gives you long enough to work it out if you don't already know.
How They Should've Sold It: The first rule of any film with a twist - don't tell anybody there's a twist.
The Hangover (2009)
The Spoilers: Amongst many plot reveals, showing Mike Tyson's cameo is something that could easily have been kept under wraps.
How They Should've Sold It: Without Tyson, obviously.
The Spoilers: Notable for showing the last shot of the movie. Maybe the editor figured everybody had already seen the Spanish original, REC .
How They Should've Sold It: To be honest, given it's the image they used across all of the marketing, it wouldn't make much difference had they removed it.
The Spoilers: "The cops can't help you..." so abused wife J. Lo buffs up in order to take on her husband. Which is the film's last act.
How They Should've Sold It: Sometimes, a narrative is so misbegotten that there's no way around spoilers. Let's face it, without showing J. Lo's revenge, this would be just be a film in which she keeps running away from her fella.
The Kite Runner (2007)
The Spoilers: The film is about a childhood friendship torn apart by war. The trailer skips straight to the film's second half by telling us that one of the boys, Hassan, dies.
How They Should've Sold It: A little sleight-of-hand would ensure that a) the footage of Amir returning to Afghanistan could be used without being specific about why, and b) the trailer is less of a downer.
Man Of The Year (2006)
The Spoilers: Late-night comedy host Robin Williams stands for President and shakes things up. And then he wins.
How They Should've Sold It: Winning isn't everything. The comedy value of a Bulworth-style "tell it like it is" satire should be enough to hook people without giving away the mid-film twist.
The Spoilers: "I'm the only one of my kind," reckons superhero Will Smith. Look closely, though, and you'll realise that's not strictly true.
How They Should've Sold It: Technically, this is ruined only for the most eagle-eyed trailer spotters. Still, it's a failure of nerve for a supposed comedy to default to action mode, especially when the teaser trailers nailed the laughs.
The Spoilers: It's probably inevitable that the trailer would reveal that the old folks are rejuvenated by alien lifeforce, but giving away that Brian Dennehy is an alien is a bit much.
How They Should've Sold It: It's Brian Dennehy! For some of us, that's enough. No need to waste time in post-production adding an extra-terrestrial gleam in his eye.
Muppets From Space (1999)
The Spoilers: "They all had their place in this world, except for Gonzo." Good job this trailer is on hand to pre-empt the film's big reveal of the Great one's family.
How They Should've Sold It: For fear of repeating ourselves… Avoid the final act. Bunch of Muppets.