One of the classic ways to build dread and tension in a video game, "Dear Diary, I'm Being Murdered" allows the player to read or hear another character's last thoughts before they are brutally and savagely murdered. Rather than show the actual death on screen, DDIBM lets the player listen to the killing in an audio recording or read it in text form.
This has proven to be an effective way to add drama and tension to a game due to the fact that it forces the player to imagine just what is happening to the character on the other end of the recording/book, making the actual murder seem more gruesome and horrifying than if they had just watched it in cutscene form.
One of the earliest examples can be found in the SNES RPG Chrono Trigger, when you happen upon a diary which has the records of a man trapped in a sewer. When he makes any noise, water-dwelling monsters attack him. In the end, he decides to commit suicide by screaming. This clues the player in that they must avoid several objects lying around the area which make noise, including the signature chime of walking into a save point. Oddly, though the diary states the man is trapped, it is quite easy for the player to leave once they reach the end of the sewer, the hatch to the surface isn't even locked.
The earliest spoken example of this occurs in the CD version of System Shock. As the protagonist makes his way through a damaged space station, he comes across recorded journals of different space station members.
A more recent example can be found in BioShock; Dr. Yi Suchong recorded an audio log complaining that he's having trouble finding a way to make the Big Daddies bond with the Little Sisters and want to protect them. He is interrupted in his recording by a Little Sister, and he slaps her in irritation. As it turns out, his most recent attempt at the experiment worked perfectly, as he is immediately and brutally slain by the nearest Big Daddy, all caught on audio tape.