People normally take trailers as the "tip of the iceberg" of their movies. 'Tip off the iceberg' in the sense that we would be expecting way more than what is offered in the trailers. So coming into the actual film and finding that there isn't much more of what was shown in the trailer is very disappointing.
However, it does seem like a movie with a very intriguing concept, and I might as well consider it.
Yes, trailers often show the movie completely and when we watch it it's kinda disappointing even when we like it, like happened to me with this one.
You should watch it, it's very good.