A genre of exploration-focused games, usually featuring a large interconnected world. Access to certain areas and defeating certain enemies requires items found elsewhere, necessitating exploration and defeating enemies to obtain them. These games are usually side-scrolling platformers or viewed from the top-down, although they can be found in 3D as well. Many borrow features from Roguelike games, such as permanent death. Named for two pioneers of the genre, the Metroid and Castlevania series.