The original Metroid and Castlevania both turn 40 years old this fall. As the two series most responsible for creating the “metroidvania,” we’re taking this occasion to take a comprehensive view of the popular genre. This is Metroidvania Week. Since their inception 40 years ago, fate has intertwined the extraterrestrial exploits of Samus Aran and the Belmont family’s fiend-fighting over multiple generations.