In all games, the following are needed: gameplay, graphics, sound/music, controls, etc. But something else that should be recognised is emotion. By that I mean, how emotional did you get when playing the game? Did you feel angry, sad, happy, depressed, and so on? Emotion is a VERY big (and neglected) element in video games. Just imagine for a moment that in the game the hero's close frend has just died, and the hero is very sad. Now imagine that after that, the game goes onto a happy level, with pretty happy things, and a generally "cute" atmosphere. Pretty weird huh? In that instance, the player got pulled out of the mood and got the impression that the sadness was pretty artificial and fake. Now visualize the same scene, but as the player continues, the level becomes dark and dreary, with sad music and a generally slower feel to the game. THIS time, the player will probably be much more affected by the event and will be all the more depressed, because the atmosphere matches his mood!
Atmosphere can make the gaming experence much more realistic, but how do you MAKE atmosphere? The trick is to use two senses together: hearing and sight. When mixed properly, the result can make an impressive effect. If you want the player to feel angry, use lots of hot colors, and heavy metal music. If you want to make the player sad, use dull colors, and slow, sad music.
Another part of mood is understanding your colors. Soft colors will make the player feel calm and happy. Harsh colors such as lime green, electric blue, and so on, will wake the player up, keeping him from being bored. "Hot" colors will make the player feel angry.
Sound and music also play a big part in video games. To energise the player use fast-paced music. To make the player feel sad use slow, drawn out music, and to give the player a happy feeling use light, joyful music.
A few games in which to study mood are Alone in the Dark, Sonic the Hedgehog, Rayman, Jekyll and Hyde, (for the PC)and American Mcgee's Alice. I hope that this article has helped you with your creating, so good luck, and happy gaming!