"The other cool thing was the PDA. All FPS games have little clues and such that you can access; locker codes, door codes, access points, useless bits of information that are just plain entertaining for a while and then turn to just plain annoying. DoomIII was no exception. The PDA is your best friend at times. Often you would come across a dead or dying NPC and his PDA would be lying there for you to download the info off of. There were audio logs the NPC¿s had made and security access codes and e-mails from other NPC¿s. I quite liked the way these were done; the emails often included spam and useless (to the game anyways) letters from home, but often they had little nuggets of information buried in there."