FEAR's story is linear and requires fairly specific timing of events and combat situations, but the design team was determined to create the sensation of an open ended environment. "We wanted to craft a world where players feel motivated to proceed but not feel like we are leading them by the nose" (John Mulkey). To do this, the level designers created obstacles that the player could approach from various directions. Whether the obstacle was a fight or a puzzle, the designers wanted the player to have some freedom in determining the solution. Multiple entry points into battle areas and various solutions to physical puzzles (jumping, button pushing, unlocking doors) added variety and pleasant uncertainty to the game play.

The design team was able to create further variation in game-play by creating levels that allow FEAR's A.I. to show off their dynamic decision making. Multiple entry points are both a blessing and a curse for a player in FEAR. While it allows the player to tailor their attack strategy to their style of play, it also opens up options for the enemy as well. The A.I. is spatially aware of their environment and will take advantage of opportunities to circle around behind you while you are engaged in combat with their squad mates. The A.I.'s dynamic real-time planning in an environment rich with cover and flanking potential creates a combat experiences that will continually surprise and challenge the player.

Weighing in at approximately 550MB, the demo will feature two maps: Factory, which will be a deathmatch map, and Facility, a capture the flag map. Both maps will allow for dedicated servers and 16 players to join in action, although LAN play will not be supported. Factory will also support team deathmatch, slow-motion team deathmatch, and slow-motion deathmatch, while Facility will also support slow-motion capture the flag. No keys will be necessary for either map.