Sounds and music in a game can either completely immerse the player, or make them jarringly aware of the unnaturalness in the game world. Sounds must convey and enhance the action experience; flow naturally for what is present on the screen; and contribute to the scene and world building. If a character is walking on wood with heavy boots, it shouldn't sound like soft leather on dirt. People can tell when something doesn't sound quite right, and it causes them to become uncomfortable. To keep the player engaged with the game, a good sound design is crucial. 

Background music adds to the atmosphere of the game. What is the character doing or how are they feeling- what is the emotion you are trying to convey to the player: is it sad? nostalgic? anxious? ecstatic? An upbeat music piece can indicate a feeling of joy or a slow piece in a minor scale can indicate sorrow or eeriness. Many players remember playing specific games or recall certain parts of a game where the background music and sound effects really captivated them. In addition to background music in games, background music for voice acting clips can support the emotion in the script and set the mood for the listener. The music can fill in the awkward silence of just a person reading the script, and instead transport the listener to the script's world. 

Finally, voice over can play a huge role in games by giving life to characters. Just the same, it can also break a game if the voice acting is stiff, emotionless, or the voice doesn't fit the character's appearance and personality.