The poisonous fog mechanism described below appeared as a specific playstyle in the previous section, and rather than repeat the mechanism itself, this section will focus on the design implications of the system.
Why Poison Fog was chosen as a form of pressure
In ROOM-9, the Poison Fog is designed to be a persistent, ambient pressure that is not under the control of the player. Unlike a traditional countdown or clear penalty mechanic, the purpose of the poisonous fog is not to tell the player how much time you have left, but to keep the player in a constant state of being chased.
Early on in the design phase, I also considered using a digital countdown prompt, but I realised that this type of design tends to direct the player’s attention to counting and planning out the remaining time rather than intuitive judgement itself. In contrast, the poisonous fog makes time difficult to measure accurately by gradually taking up space. The player is unable to tell how much time is left until it is ticking away.
This ambiguity is formally what the poison fog mechanic exists for. By not providing clear information about time, it forces the player to make choices under uncertainty, bringing judgement closer to a reaction on an intuitive level.
Impact of the poisonous fog on player behaviour and judgement
The continuous advancement of the poisonous fog will have different effects on players at different stages. At the beginning of the game, when the poisonous fog is still some space away from the player, the player is more willing to try and make trial and error.
As the poisonous fog gradually gets closer, the player’s behaviour will undergo some changes. No longer trying at random, choices that could have been made with hesitation are now compressed into decisions that need to be made quickly. During this stage, it is difficult for the player to fully analyse every choice and begins to rely more on experience and feeling.
This change is naturally shaped by the system. The poisonous fog doesn’t directly punish a particular misstep, but it will magnify the consequences of every lapse in judgement. Once time is consumed, it cannot be retrieved.
From a design perspective, what the poisonous fog limits is not the player’s freedom of action, but the way the player thinks. Constantly compressing the player’s thinking time forces the player to gradually use intuitive thinking.
Poison Fog Mechanism
This paragraph has already appeared in the OVERALL GAME DESIGN section and is repeated here.
The poisonous fog will gradually spread downwards from the top of the corridor. The player can clearly see the poisonous fog advancing and can feel it as a constant reminder that time is passing. The Poison Fog does not cause damage at the start, but once it is fully released, the player will lose the game.
- The fog starts the timer as soon as the player enters the corridor.
- There is a total of 15 minutes from start to finish, and the player needs to successfully gather the keys to open the last door within this limited time. There is no timer window in the game to remind the player how much time is left.
- The fog in the room is timed separately from the fog in the corridor. The fog in the rooms is timed as soon as the player enters the room, which is two and a half minutes for each room. When the player completes the level in the room, the fog in the room dissipates, but the fog in the corridor is always spreading, and the fog in the corridor doesn’t stop when the player enters the room.
- The fog advances at a constant rate and does not pause or slow down or speed up due to player behaviour.
- After the toxic fog completely covers the area, the player will fail. Failure in the room returns the player to the corridor, where they can re-challenge, but if the poison fog covers the corridor, the entire game is lost.
The Poison Fog is not an attack-based mechanic, but rather a constant source of stress. It serves not to punish the player for operational errors, but to limit the player’s inability to have unlimited thinking time.