Metroidvania
also known as (for better, or worse): 
Castleroid, Metrovania
The name 'Metroidvania' originates from the beginning of the Igavania era of the Castlevania series, when the games seemingly took inspiration from the Metroid series, and became more exploration-based. The term has since become a (misappropriated, and ugly) common descriptor of any game in that style: a 2-D platform game with adventure game elements (a genre well established by many games preceding Symphony of the Night).
Examples
See Also
- Metroidvania on Encylopedia Gamia.
- bastard metrovaniae - GO forum thread.
- Freeform metrovanias - GO forum thread.
- Fuck Metroldvanias. - KOP forum thread.