What is the purpose and function of a film opening?

The opening to Tomb Raider shows the protagonist and what they are like in the film. It shows their personality and tells us something about their occupation/hobby which is the purpose of a film opening as well as communicating and creating narrative enigmas.

Right from the start the opening gives us plenty of narrative detail with the scene starting with an extreme close-up that slowly zooms out and twists to show us the characters face and her orientation. This immediately makes us wonder what she is doing and where she is. These enigma's are answered very quickly with a long shot that shows us a tomb which she is hanging into on a rope. A big close up shows and artefact like object which we assume she is looking for. The purpose of this is to show the viewer the main character and show them how acrobatic and active she is.

We see a close up of her eyes as they look left and right telling us she is fairly wary and cautious of her surroundings. A close up of her feet when she is running makes us assume she is confident of her decisions and may be slightly hasty. When she slows down we are shown a point of view shot of the artefact. At this point a tilted down mid-shot shows her hands ready to grab the dual pistols she has. This shows us that she is ready for whatever may happen. There is no music in this part of the scene which builds tension.

Everything slows down when we see a point of view shot of something above her looking down at her. We see rapid cuts between many different shots to show the immediate excitement and speed presented by the entrance of the robot coupled with the louder, faster paced non-diagetic music. We see a point of view with effects for the robot in a shot reverse shot between the robot and the main character. The purpose of this is to show the viewer that the robot is looking for her for whatever reason.

Later in the scene, the protagonist reloads their gun, but, instead of just reloading we see close-ups of every stage of the reload. With everything else out of focus to make viewers watch and emphasise that she is reloading. We also realise that the non-diagetic music stops and the diagetic sound of the gun reloading is louder to make it more noticeable and dramatic which gives the viewer a rest from all the excitement that is happening.