Since the game is in "first person", a player does not see himself or herself on the main portion of the screen, except for his or her own hand when certain [[weapons]] are selected.
In Doom, a marine's face is shown on the [[status bar]], where it reflects the player's health (becoming progressively bloodier as the player's health falls) and reacts to events such as being attacked, stepping on a [[damaging floor]], or finding a weapon or powerup.
The player moves in response to the keyboard, mouse and/or joystick at either walking speed or running speed. The forward/backward speed is 25 or 50 map units per game [[tic]]; the sideways speed is 24 or 40 (or, in some cases, 50). These movements can be combined: see [[straferunning]].