Conventions of a film opening...

So from my research into film openings, I have found that the typical conventions are:

• The main characters or some of the main characters should be introduced in the opening
• Action and enigma codes should be used but leave the audience wanting to know more - answer some questions
• The length/content of the title sequence will convey the type of film it is 
• The genre of the film is set in the opening
• The opening needs to hook the audience so they WANT to carry on watching
• A problem should be introduced in the opening aka disequilibrium. The rest of the story/film will then show their quest to find the state of equilibrium again.