As a film goes from beginning to end there are things a filmmaker can do to augment or negate changes in story and character. Depending on how the filmmaker feels about how the story progresses they will alter the production accordingly. This is not the kind of thing the audience would notice necessarily but rather something felt on an un-conscious level that nevertheless makes an impact.

Color

Color can affect emotions dramatically. Absence of color is absence of life. If things turn dire in your film you could begin with a monochrome color palette and have the film wind up technicolor, this would soften some of the more somber elements. Conversely a sad film that starts with full color and ends in greys can make the movie that much more downbeat.

Exposure

A film that gets more horrific as it moves along could be intensified with progressively darker shorts. Obscure images forces us to fill in the blanks and that can be more terrifying than reality. But a film that gets more bloody or gory might need to become brighter to make these elements more vivid and detailed.

Shutter Speed

Shutter speed changes are especially noticable with rapid motion. Higher shutter speeds keep details in motions where lower shutter speeds tends to blur. For a character that gains superhuman strength in the course of a story a lower shutter speed would add a subtle blurring to any motion they make and thus the impression of being faster than it actually is. But as a character gains physical power it might be necessary for us to be able to see more clear the things they do with the strength so going to higher shutter speeds might be called for.

Angle

Angles connote stature of the subjects the camera is capturing. One example of how a progression of angles could be used in conjunction with the story is a tale of rags to riches. Up angles on the main character in the beginning will evoke feelings of powerfulness and as he descends into poverty the angles change until they are looking down upon him as parent looks upon a child. If a filmmaker does not see the character's slide into the poorhouse as a bad thing they could reverse the angle progression and make this character seem more powerful as he lose financial power, an ironic comment on the situation.

Lens

In a film where the protagonist slowly loses privacy in the course of the story, a progression of camera lenses could be a welcome addition to things. The story of going from an anonymous person to celebrity could be shot in such a way as to begin with tight telephoto lenses that compact figures and only show a little detail at a time to later on using wide angle lenses that make more details in a scene visible, just as you become a celebrity more of your life is visible. For filmmakers that see becoming a celebrity differently they might reverse the progression to where the changing to longer lenses evokes feelings of the claustrophobia celebrities feel when they have to stay indoors to avert attention.

Camera Distance

Related to lens choice is the distance the camera is from the subjects. A character that becomes more evil as the story progresses might have the camera steadily move further as one might distance themselves from a bad person in real life. An interesting comment on the nature of evil would a motif that brings us close to this person as the movie plays on.

There is a lot filmmakers can do to add to nuances to their film that can make the difference between a good and great film. Do not be worried about it not being noticed, the visuals should be in service to the story and if done tastefully they will not battle the plot for attention and instead will work together for greater effect.