# Gates

In level design, a **gate** is anything that blocks player [flow](https://book.leveldesignbook.com/process/layout/flow), usually along a [critical path](https://book.leveldesignbook.com/process/layout/criticalpath). 

Gating is an abstract concept, it is not necessarily a literal gate or door. It could be a magic barrier, an NPC blocking a doorway until you complete their quest, or an avalanche of rocks that falls behind the player. Anything that blocks player movement is functioning as a gate.

Gating is also a verb: *"we have to gate the player inside the arena until they complete the boss fight..."*

## Gate types

### Strictness

* **Hard gate:** players must always complete the encounter with no shortcuts *(e.g. wait until a timer elapses, defeat all enemies, loot a key from a defeated boss)*
* **Soft gate:** can potentially exit early, but must usually complete the encounter *(e.g. exit mechanism requires staying in a vulnerable position, so most players clear the arena first)*
* **Hidden exit:** the player must explore the arena to find the exit *(e.g. an exit hidden in a corner that most players won't notice until after clearing the arena)*

### Direction

* **Forward gate:** player's forward progress is blocked.
* **Backward gate / one-way entrance**: player cannot backtrack.

## Lock and key gates

A **lock and key gate** is a hard gate that prevents the player from passing through until they find the "key" somewhere else in the level. This key is abstract -- it can be a literal key item that the player picks up, or it could be a button.

Some best practices with implementing lock and key gating:

* **Show the lock before the key.** When the player finally finds a key, they might remember the locked door they encountered earlier. If you do it the other way around, it will feel less like the player solved a problem, and more like they accidentally stumbled on the lock with the key already.
* **Remind the player about the lock when they get the key.** Maybe the key is on a balcony overlooking the lock, or the button is aligned with a window facing the lock. Nonrealistic projects could script a brief cutscene that shows the unlock.
* **If the lock requires multiple keys, the lock's visual design should hint at the key count.** For example, a locked door that requires three keys should have three keyholes.

## Shortcuts

A **shortcut** is a hard gate that the player can unlock from the other side, allowing easier backtracking and/or better flow between areas. Exploration games often feature one way doors, climbable ladders that drop down, or elevators that turn on.