Metroidvania
Also said as Search action
One large connected map, where new abilities open paths you already saw and could not take. It promises the pleasure of remembering a door. The name joins Metroid and Castlevania.
The world itself becomes the progress bar. The ledge you could not reach an hour ago is a promise, and keeping it feels better than any reward handed to you.
Say it
“Make it a metroidvania: show the high ledge in the first room, give the double jump 20 minutes later, and draw the ledge on the map so the player remembers to come back.”
Where you’ve seen it
Metroid (1986) and Castlevania: Symphony of the Night (1997) gave the genre its name. In Hollow Knight (2017), the Mantis Claw lets you cling to walls, and suddenly shafts you have walked past for hours go somewhere.
Not to be confused with open world
An open world lets you go nearly anywhere from early on. A metroidvania is locked by what you can do, so its order is hidden in plain sight and opens up slowly.