The human eye has a relatively wide field of view—you can see someone approaching from the side through your peripheral vision. When you’re playing a game, your character doesn’t have this same peripheral vision, because you’re playing on a screen that takes up only a portion of your own field of view. That means you won’t see as many enemies coming up the side, or you may even feel motion sick when moving the camera around fast.
Adjusting the oft-ignored Field of View setting can help with this, provided your game offers it. Widening the field of view may add a slight fisheye effect to the edges of the screen, but you’ll be able to see more of the game world, and it may help reduce that nausea. (It’ll also hamper performance a bit, since the game has to render more objects.) The ideal field of view is dependent on