A short theme linked to a character, place or idea

What is diegetic music?

Music that comes from inside the story, so the characters hear it

What is non-diegetic music?

Music only the audience can hear

Music that matches the action exactly

A repeated ostinato with dissonance and a crescendo

Players can stay in one place for a long time

Music that changes with what the player does

Film music creates mood, builds tension, shows what characters feel and tells the audience what might happen next.
A leitmotif is a short theme linked to a character, place or idea, which comes back when they appear. Famous examples: the two-note shark theme in Jaws and Darth Vader's march in Star Wars (both by John Williams).
Underscore plays under the action. Non-diegetic music is heard only by the audience; diegetic music comes from inside the story (a band playing in the scene, a radio).
Mickey-mousing is when the music matches the action exactly, such as a falling scale as someone falls down stairs.

Tension: dissonance, chromatic notes, low pedal notes, ostinatos, tremolo strings, rising pitch and crescendo.
Heroes and adventure: brass fanfares, major keys, strong dotted rhythms. Romance: strings, slow legato melodies. Sadness: minor keys, slow tempo.
Timbre matters: the same theme can sound heroic on brass or lonely on a solo flute. Composers also use synthesisers, choirs and sound design. Hans Zimmer and John Williams are famous film composers.
Some films reuse music from the Western classical tradition, chosen for its mood.

Game music must loop smoothly, because players can stay in one place for a long time.
Adaptive (dynamic) music changes with the gameplay: faster and more intense in a battle, calmer when exploring, with short stingers when something happens.
Early consoles used chiptune: simple 8-bit sounds with a few square-wave channels. Koji Kondo's music for Super Mario Bros. and The Legend of Zelda is famous.
Modern games use full orchestras, choirs and electronic sounds, just like films.

Leitmotif: A short theme linked to a character, place or idea.
Underscore: Music played under the action of a scene.
Diegetic music: Music that comes from inside the story, so the characters can hear it.
Non-diegetic music: Music only the audience can hear.
Mickey-mousing: Music that matches the action exactly.
Ostinato: A short pattern repeated over and over.
Adaptive music: Game music that changes with what the player does.
Chiptune: Simple electronic music from early game consoles.

What is a leitmotif?: A short theme linked to a character, place or idea: Like the two-note shark theme in Jaws.
What is diegetic music?: Music that comes from inside the story, so the characters hear it: Such as a band playing in the scene.
What is non-diegetic music?: Music only the audience can hear: Most underscore is non-diegetic.
What is mickey-mousing?: Music that matches the action exactly: A falling scale as someone falls, for example.
Which device is most likely to build tension?: A repeated ostinato with dissonance and a crescendo: Tremolo strings help too.
Which instruments most often play a heroic theme?: Brass: With fanfares and dotted rhythms.
Why must video game music loop smoothly?: Players can stay in one place for a long time: The join should be impossible to hear.
What is adaptive music in a game?: Music that changes with what the player does: Faster in a battle, calmer when exploring.