To what extent are trailers accurate to the film?

When it comes to trailers, they can either be misleading of the finished film, or completely spoil it. Both of these tend to lead in disappointed viewers either before or after the film's release. Here are some examples of a trailer that was too misleading of the film and a trailer that spoiled the whole film, and whilst they do not fall under the genre I am studying they are still interesting to analyse.

Misleading Trailer, Godzilla (2014)

Directed by Gareth Edwards and staring Aaron Taylor-Johnson, Elizabeth Olsen and Bryan Cranston. Godzilla was one of the biggest films of 2014, earning over $529 Million which was over three times it's production budget and getting all-round good reviews, kickstarting a franchise with a sequel coming out in 2019. Despite it's success it is notorious for it's misleading trailer. In which it is implied that Godzilla is the one wreaking havoc upon the world and is put forward as an antagonist. However, after watching the film you can see this isn't the case In fact the title character doesn't appear until about 40 minutes in and only has about 10 minutes of screentime in the 2 hour film. The main antagonists of the film were these 'MUTOs' which were a new kind of monster made for the film. The problem is they didn't even appear in the trailers for the film, except maybe for a frame or two. In fact one scene of Godzilla fighting one of them as doors closed on the battle was edited to just show him roaring forbiddingly at the camera. This could be justified however, as Edwards could have just wanted to avoid spoiling the story. Another misleading part was the excessive use of actor Bryan Cranston in the trailers. They set him up to be one of the main characters when in reality he was killed off quite early on, without doing too much for the story. This was a little more deceitful as they most likely did this because Cranston is a popular actor and this would have drawn audiences in.

Spoiler-Filled Trailer 

There have always been criticisms of spoiler filled trailers. They take away the fun from the film and leave no point in watching them. A notorious example of this is 2018's Jurassic World: Fallen Kingdom which, whilst doing very well at the box office, was critically panned worldwide. Universal released its first trailer in December of 2017, which was not too spoiler heavy, showing us mostly footage from the first half of the film. The second trailer however is where things went south. In just a minute and a half the entire plot of the film was revealed, this made the film less impactfull, for example the plot twist of the main characters being betrayed and left for dead on the island was supposed to be a big moment, but it was ruined by the trailers, meaning it meant nothing for viewers. It also spoiled the second act revealing that the new hybrid "Indoraptor" escapes and wreaks havoc on the manor was also spoiled, leaving most audiences waiting for them to get to that part rather than pay attention to what was going on in the film at that point. However, like the previously mentioned Godzilla, they did do a similar thing with actor Jeff Goldblum, reprising the role of his character Dr Ian Malcom, as they did with Bryan Cranston, implying they were both key players in the film when in reality were in it for hardly any of the film. Although I suppose you could count it as a spoiler as basically all we see of Goldblum in the film was shown in the trailers. 

Altogether I can see, by these trailers what percautions I should take when it comes to making my trailer, granted I'll be doing a different genre and there will not be a completed film to spoil, I should still take into conideration where these ones went wrong.