The gaming equivalent of a movie trailer isn't the cinematic trailer but the demo.
This gets mentioned almost as an aside about halfway into the article and then taken for granted from there (as the article veers into a discussion of how more games need demos), but not much effort is really spent arguing the point, and I'm still left thoroughly unconvinced about this core premise.
Certainly a demo is the best option we as players generally have for getting a feel for what a game's really like to play, far better than screenshots or trailers (whether mood or gameplay). But it's the other side of the equivalency that I'm skeptical of - who ever said that the purpose of a
movie trailer was to give you the best feel for that the movie's like? The movie trailer's job, plain and simple, is
to get you to go to the movie. It's certainly not to convey the plot of the movie, or to suggest similar movies, or to tell you about the movie's acting or cinematography. That's not to say that it won't occasionally do those things, but they're secondary to the trailer's purpose.
I would argue that the game demo's closest comparison on the movie side is the review or the synopsis - both designed to give you a more detailed impression of what you're in for when you go to the film. The typical movie trailer/TV ad, I'd say, corresponds to the gameplay trailer: both give you enough detail to make a reasonably informed decision without giving too much away. And the game world's cinematic trailer corresponds to the classic 'teaser trailer', be it logo or otherwise: just enough information to whet your appetite about the goings-on.
Can gameplay trailers be deceptive? Absolutely, as can 'atmospheric' trailers (though arguably those aren't deceiving because they're not even trying to tell you what playing the game is like), and as can demos themselves - people have pointed out
Brutal Legend already, but I'll also point out that a number of reviewers chided
Flower when it came out for getting much darker than the previews they'd played had led them to believe. But cinematic trailers can be at least as deceptive; in fact, I'd claim that cinematic trailers are more often cut to be actively deceptive, presenting movies as something they're not in order to draw more viewers; think of the parody trailers for
The Shining, or for a more real-world example the atmospheric trailers for
Cloverfield or
The Happening that completely omitted those films' doofy villains. But the point still holds that if you go into a movie having only seen ads and trailers, you're at least as likely - if not more so! - to be going in with a mistaken impression of what you're getting than if you pick up a game having only seen gameplay trailers and screenshots. This isn't even unique to movies; heck, even this article's trailer could be considered deceptive - I was promised a discussion of why trailers aren't enough and how to try and judge a game using minimal public info, and wound up with a mini-rant on how more games need demos!
So why do we care so much? Why do we demand demos for games but not, say, extended samples of movies (say, the first 15 minutes or so)? I think there are a couple of factors at play. One, you could make the argument that a 3-minute trailer at least holds a greater percentage of the screen time of a 90-minute movie than the 2-minute gameplay trailer for a 25-hour game does, and that the demo lets you see a comparable proportion of the game's content. But again, movie trailers aren't trying to represent the movie's content; they're 3 minutes of non-spoiling high points, carefully selected to try and make the movie as appetizing as possible - and I don't know of many demos that are constructed that way, any more than I know of any movie trailers that are just the first 3m of the movie. (Unless there was a
Superman trailer I'm forgetting...)
More to the point, though, the reason that games have demos is because the stakes are that much higher. If you get deceived into watching a
Cloverfield because you're expecting a spooky psychological drama, you've wasted ten bucks and two hours of your life. If you get deceived into buying a
Brutal Legend by its trailers (or even by its demo!), you're out sixty bucks, and probably 3-5 hours by the time you realize that you're not getting what you expected. We demand game demos because we put an investment into games - both financial, temporal, and arguably even emotional - that we just don't have to lay out for movies.