This is an ever relevant and interesting topic to talk about and the short answer is yes, of course they do but also no, not all of them do, with the exception of notable films like Star Wars The Force Awakens, Tomorrowland that don’t show much, leaving you guessing while you have films like Jurassic World and Terminator Genisys on the other end of the spectrum.
It’s interesting to think about because a spoilery trailer doesn’t have to be a bad trailer, I still think Jurassic World looks fantastic and I can’t wait to see it, though I roughly know what happens and have seen some big parts of the movie but there’s always a line that can be crossed, when a plot twist or surprise is revealed in a trailer… that’s too much. Trailers’ by nature have to be revealing, they’re the big portion of a movies marketing machine, showing audiences what to expect and why they should watch it and all of that is logical but a trailer doesn’t have to show everything.
I think there’s been a trend in recent years, I’d say it’s a late 2000s onwards trend to hype up big movies to stellar standards to drum up publicity, which for some studios means showing just about everything they reasonably can in a trailer, or you know just release 3 or 4 trailers as you do, hello Age of Ultron. But yeah it’s a trend movie going audiences can do without in reality, from a logical standpoint we as audience members don’t want movies spoiled for us before we see it, we don’t want to see major plot points occur or twists.. we want a snapshot/layout of the film to get a feel for what it will be like. Terminator Genisys is the big recent example, the most recent trailer showing the big plot twist with John Connor being an android (because science?) in the present, cool twist but seriously, we should’ve found that out while watching.
Why some big studios think that means showing just about all major plot point in a trailer as well as releasing 3, 4 or 5 trailers is necessary is beyond me, but it’s really not needed in the long run, The Force Awakens goes to show that all you need is a great trailer (or two) to build sufficient hype for a film. And okay Star Wars is one of the longest running and most popular franchises of all time but the point remains, filmmakers should take a note from directors like JJ Abrams and Brad Bird, teasing the film with snippets and keeping them guessing.
Granted the JJ Abrams trailer style just won’t suit every film, especially big dumb blockbusters, but still, its nice to see a film not knowing there will even be a twist and not remembering a big action scene because you saw it in a trailer. I guess it’s to be expected that movie execs and studios want their films to be marketed in ever effective, more interactive ways but that doesn’t include super spoilery trailers, something the movie goer can definitely do without.