Portmanteau of Metroid and Castlevania, thought 99% of the time written as Metroidvania. I prefer Metrovania (just because). 2d-action-adventures of the platformer variety most of the time, that sport one world divided into smaller, strongly interconnected sections, that can be entered and re-entered at will, mostly (fake) non-linearity when it comes to exploring the world, items that open up new paths, lots of backtracking all over the map and lots of platforming.
