|unfortunately only applies to the first Dead Space|
Sound for games, i believe can be broken into two catergories. The first being "general soundtrack" and the second being "sound effects". General soundtrack is the overall blanket of sound that games have. The type of sounds that you would sing as you would walk down the street, like the skyrim main theme or the mario theme or something. Although it is generally used as background noise it can be very good for rooting the type of atmosphere the producers are trying to make. Skyrim for example used the main theme tune when you were scuffling with dragons to help the feel of "holy shit i'm fighting a dragon". Sound effects in my opinion is what really gives a game some "real" feeling. The dragon fighting scene for instance with the main Skyrim theme is pretty cool however you aren't all emmersed without the sounds of the dragon's roar or the clashing of metal to dragon scale. The best use of sound effects to create immense emmersion (try saying that five times) would have to be Battlefield 3 by EA.
A video where the lead audio designer for Battlefield 3 talks about his experiences in making the sound for their games. The most important thing in my mind from this video is the fact that they really had to experience what a battlefield would be like. If you can make an impact on the lead audio designer, make him really feel what its like on the battlefield, then you've already won half the battle of making honest realistic experienced sound.
A video i found about the layering techniques used by the team when making Star Wars Unleashed 2. This technique is used by nearly every game and movie that I've bothered to watch the "behind the scenes" of. In games especially, layering is used to boost the sound above the layers of ambient sounds and music. It helps create sound with more depth and character than the recorded ones. A good example of how layered sounds is used would be from the game League of legends. Rengar is one of the "champions" you are able to play as, a bipedal lion with an affinity for murder is the briefest description of him i can muster. His roar, the subject of layering sound, was created using layers of real lion roars and explosions to make him sound the the big badass character he is .