Genre Difference, Repetition and Simialrity

The thriller genre is different from most other genres because on the surface, many of them look entirely different from each other. Here are some examples:

These films are all classified as thrillers but are very different. The far left film is about an ex CIA agent on the run from the CIA. The middle film is about a group of businessmen who do their work within peoples dreams. The far right film is a political battle between President Nixon and a TV interviewer. The key differences are the variety in violence levels, narrative, and the character differences. 

However, despite these differences, these films are all very similar. They all successfully are very tense and suspenseful, and keep the audience on the edge of their seats at all times. The three all have, in one way or another, a main antagonist included, whether its the ex-president, the CIA or an enemy of the protagonists.