Much like in film, television, and literature, the knowledge that one of your favorite characters can die immediately raises the tension. This is especially true in games, most notably in titles that hinge on player choice. Every decision gains a kind of weight, each feeling much more important, even if some really only appear to be. However, even linear games benefit from this uncertainty, keeping the player on the edge of their seat as they progress through the narrative.
Example 1: Mass Effect 2 Edit
For example, in Mass Effect 2, one of the greatest moments of tension is the final battle. All of the decisions that the player has made leading up to, and during, this moment have drastic consequences. Where one player may end up finishing this sequence with their entire team intact, others may begin Mass Effect 3 with several key characters present only on the list of the dead displayed on their ship.
Example 2: Call of Duty 4: Modern Warfare Edit
Most people will agree the real gut punch and arguably the best part of the Call of Duty series storyline was the death of Sergeant Jackson in the 'Nuke Scene' of Call of Duty 4. This scene not only shocks the player be reinforces the randomness and feeling of helplessness soldiers feel at time. The death is perfectly timed at the end of the mission when the player is feeling the maximum sense of achievement and safety. This moment then makes the player consider how many more of the playable characters will survive the rest of the game.