Prey: Let a Disguise Change What the Player Can Do

A disguise in the game Prey can alter a character's appearance, influence observers' reactions, and unlock new actions. When a player transforms into a smaller object, the new form may imply greater capabilities than the game actually supports. In a February 2017 feature, lead designer Ricardo Bare demonstrated using Mimic Matter to evade an alien, set up a trap, or shrink to fit through a small slot.

The March 2017 powers guide added that while disguised, the player could move but might draw attention, accompanied by a constant psi cost. These descriptions outline the game's mechanics and question how the disguise impacts gameplay rather than attributing its success to a specific factor. The prototype design checklist includes three key points: Appearance, Permission, and Exposure.

The appearance refers to what the player transforms into, permission denotes what actions the new form can perform that the regular character cannot, and exposure indicates the behavior that reveals the disguise. The proposed design checklist is not a depiction of Prey's internal workings, but rather a guide for creating a convincing visual transformation and testing the rules of the disguise.

The checklist suggests separating the game's rules into separate decisions: appearance, permission, and exposure. A convincing visual transformation sets player expectations, while a clear explanation of the rules prevents confusion. The prototype should start with one form and one useful permission to test whether players grasp why they would choose it.

A fictional space-station storeroom serves as an example of a prototype room, with a normal-sized character and a small disguised form that can pass through a low opening. An observer patrolling the opening should react differently to the two forms, providing clear feedback when the player is noticed and a safe retreat area. Testing the prototype without a timer or resource drain allows examination of whether players understand the form and its exposure rule.

Failure points to consider include not connecting the small form with fitting through the opening, not knowing when the observer can see them, and finding stopping and moving tedious. Each failure requires different revisions. After testing, ask what the player gained from becoming the object, what could expose them, and why they chose their route.

A long corridor is important for allowing players to decline the disguise. If everyone chooses the small opening, it could indicate that the disguise is enjoyable or that the other route is unreasonably slow. Vary the corridor length to find a situation where players can express a preference. Before adding more forms to the game, determine if one transformation changes a decision in a way that players find enjoyable and understandable.