In order to refine the distinction between open-world and linear level design clear for an audience who is unfamiliar with the medium in general, I will use an example from Half-Life 2’s “Highway 17” chapter. In particular, I will focus on one space within this environment – the tresses of a bridge that spans a body of water (see above image).

In this environment, the player must navigate across structural support beams beneath a bridge, reducing the “playable space” to a very narrow physical range. If the player walks off of the tresses, they will plummet to the water below and die and must replay the level, so in this specific case, the tresses are the primary (and only) means of advancement. In addition to diegetic elements that enforce the dizzying scale of the space – including the sound of the bridge vibrating as vehicles pass above, the sound of wind, atmospheric fog, and other “evocative narrative elements” (Nitsche) – the narrow scale of the space forces the player to interact with it in certain and limited ways. Once the player reaches a platform with a small watchpost in the middle of the underside of the bridge they are less exposed to the surrounding environment. In this room, with four walls, a ceiling, and a floor, there is a sense of security in contrast to the precarious beams that the player had to traverse to reach this point. The player must cross the other half of the bridge’s tresses to reach the other side and advance through the game, whereupon they must traverse back to the other side of the bridge to advance even further. On the second time around, the player is surprised by an enemy aircraft targets the player on the tresses and fires a swarm of rockets. The physical space (the underside of a bridge) never changes, and the playable space in the game is highly linear. The player can not move anywhere except the tresses, and though this spatial constraint inhibits movement, it certainly does not inhibit game play nor does it limit the player-created narrative. Doubling back on the tresses of the bridge is an example of “breaking … up [a player’s spatial progression] and returning [them] to previous areas” (Abram, Rathbone 2008, 11-12), a practice that institutes an artifice of non-linearity.