Genre is a way of classifying movies by like brand. Every genre has its own caucus for story, character, setting, and theme. Westerns, for example, share similarities in character dilemmas and thematic predicaments. The difficulties faced by characters in a western are much different than those faced by characters in, say, a romance.
Genre circumscribes what the audience are looking forward to when they go to watch movie. If they pay to see a crime movie, that is what they want. If it turns out to be a horror story, there is going to be crisis in the cinema.
Next time on the movie genre, we are going to be looking at genre categories. If you need help with your screenplay or any question, feel free leave me on note on this post.