Film critics working for newspapers, magazines, and broadcast media mainly review new releases. Normally they only see any given film once and have only a day or two to formulate opinions. Despite this, critics have an important impact on films, especially those of certain genres. Mass marketed action, horror, and comedy films tend not to be greatly affected by a critic's overall judgment of a film. The plot summary and description of a film that makes up the majority of any film review can still have an important impact on whether people decide to see a film. For prestige films such as most dramas, the influence of reviews is extremely important. Poor reviews will often doom a film to obscurity and financial loss.

The impact of a reviewer on a given film's box office performance is a matter of debate. Some claim that movie marketing is now so intense and well financed that reviewers cannot make an impact against it. However, the cataclysmic failure of some heavily-promoted movies which were harshly reviewed, as well as the unexpected success of critically praised independent movies indicates that extreme critical reactions can have considerable influence. Others note that positive film reviews have been shown to spark interest in little-known films. Conversely, there have been several films in which film companies have so little confidence that they refuse to give reviewers an advanced viewing to avoid widespread panning of the film. However, this usually backfires as reviewers are wise to the tactic and warn the public that the film may not be worth seeing and the films often do poorly as a result.

It is argued that journalist film critics should only be known as film reviewers, and true film critics are those who take a more academic approach to films. This line of work is more often known as film theory or film studies. These film critics attempt to come to understand how film and filming techniques work, and what effect they have on people. Rather than having their works published in newspapers or appear on television, their articles are published in scholarly journals, or sometimes in up-market magazines. They also tend to be affiliated with colleges or universities.