Other (objects, etc.) concept

Player is required to locate keycodes - and possibly to fill in missing characters in them - to gain access to something.


Alternate names: Key sequences, Access codes, Passwords

The first video game about Keycodes was released in 1987.

Square Enix, 2K Games and Harebrained Schemes has published most of these games

There are two types of keycodes used in games: static and random. The latter is usually in place to undermine walkthroughs, forcing players to locate the keycode regardless if there's any benefit in doing so other than gaining the code itself.

A somewhat related concept is the key sequence, where player needs to simply press buttons, keys, or other triggers in correct sequence, which may or may not have been provided to them somewhere. Usually these are limited to only 3-5 keys, so they're relatively easy and fast to solve by trial and error.
* Doors
* Containers
* Keys
* Hacking - used to bybass the need for a keycode.