Bleeps and bloops
Imagine watching a move that has no sound. As the main character runs down the alley, there are no footsteps. There is no swishing sound as his arms rub his jacket. There is no screech as a car comes to a halt just before hitting him.
A movie without sound would be pretty boring, and so would most games. Sounds bring games to life. The best sound design is one where the player doesn't actually realize there is a sound design. This means crafting sound effects and music in a way that complement the game without being obnoxious.
Sound effects
Sound effects generally correspond to some event or action that is happening in the game. A particular sound often corresponds to something that the player can see, but sound effects may also occur for something that the player cannot see, perhaps just round the corner.
Let's add our first sound effects to the game. We'll keep it simple and add the following sounds:
A rolling sound as Robo moves across the screen
A sound when Robo jumps up...