As the preceding examples show, the design and creation process of audio and music for games is based on traditional composing, recording and creation practices but the assembly and delivery of the media assets requires other tools and an adapted kind of thinking and planing.
A common classification of sounds in games as adapted from film music.
Diegetic sound is heard by both the characters and audience. Also called ‘literal sound’ or ‘actual sound’.
Sound effects: car engine, collisions, explosions
Music: car radio, band playing on screen
Vocals: dialogue, voices, crowds
Non-diegetic sound is represented as coming from a source outside the story space, i.e. its source is neither visible on the screen, nor has been implied to be present in the action. Also called ‘non-literal sound’ or ‘commentary sound’. wiki
Sound effects: off-screen sound effects e.g. footsteps
Music: background music, tunes, themes (boss theme etc.)
Vocals: off voice, narration