Genres and their openings

Every film opening is different according to the certain genre the film belongs to. However, film openings are similar in terms of certain elements, according to their genre, and irrespective of genre, all film openings share a common purpose which is to capture the attention of the audience. For example, films of the thriller genre foreshadow the plot of the rest of the film in the first few minutes of the film opening. In ‘The Dark Knight’, directed by Christopher Nolan, an action thriller, the audience are introduced to the Joker, the protagonist, through a bank robbery, making it clear to the audience that the Joker is a character that they should fear as he and his group terrorize and kill civilians, and has a role vital to the film's plot. Moreover, in the film Se7en, directed by David Fincher,  the opening is a montage of clips that are not in a chronological order which gives the audience the impression that this person is doing many different things to create a file or investigation about something, e.g. getting photos and writing information. As a result, the audience feels uneasy and suspicious as it cannot see the character but it presumes that what they are doing is strange and suspicious.