singledebar

Singledebar is a term used in puzzle design and speculative fiction to describe a single, discrete obstacle that blocks progress until a specified condition is satisfied. The concept is commonly applied in interactive fiction, escape rooms, and indie video games to create a focused gating moment.

The term derives from the words "single" and "debar" (to exclude), signaling a lone barrier separating the player from progression. It is distinguished from multi-step locks or cascaded challenges by its focus on a single resolving action.

In terms of mechanics, a singledebar should be solvable with minimal backtracking and provide clear feedback when the condition is met. It may take the form of a locked door, a sealed gate, a puzzle lock, or a time gate; the required condition can be item-based, action-based, or knowledge-based. Designers aim to align the barrier with intended affordances and ensure the solution is discoverable.

A common variant is a one-time gate: once the barrier is opened, it remains passable for the remainder of the experience. Examples appear in puzzle collections and indie games where the challenge is to identify a single condition, such as collecting a key item or solving a main riddle, to unlock access.

In practice, the singledebar serves to regulate pacing, build tension, and provide a clear milestone in narrative or gameplay. It is discussed in design guides on pacing and gating, and is often contrasted with more complex, multi-layered locks. See also: barrier, gate, puzzle design.