What Makes a Metroidvania?
"It's definitely not Metroidvania."
And, "Although, this game has a map to explore it is not really a Metroidvania."
This was the first recorded time that a Castlevania developer had used the term "Metroidvania". But even more importantly, this is notable because it shows that even creators of a game in a given style may use its name differently from the fans. In his concept of a Metroidvania, Mr. Cox placed an emphasis on the RPG system of Koji Igarashi's games - which is a means of improving the main character's abilties, this being something the games are known for.
And it's not like there isn't any disparity among the fans. Sometimes it's used only in reference to the Symphony of the Night-style Castlevania games; sometimes to games that are thematically or atmospherically similar to Metroid or Castlevania; sometimes to just about any sidescrolling adventure game; sometimes only to games with one seamless, interconnected map, excluding such titles as Tails Adventure, Wario Land 3, and Castlevania: Order of Ecclesia. It's not definitively agreed whether three-dimensional games fit into the label, either.
A Metroidvania doesn't have to be a Castlevania or a Metroid game, and a Castlevania or a Metroid games doesn't have to be a Metroidvania. The combination of "Metroid" and "vania", though likely once a derisive one, is now merely a tribute to two of the most famous and prolific series containing examples of the style.
Looking at the core elements that make up the original 2D Metroid games as well as Symphony of the Night and its successors rather than their secondary distinctions, the most important elements have to be the following:
1) Its sidescrolling map is interconnected, nonlinear, and explorable. It may possibly contain several of these connected by a non-sidescrolling overworld map or stage-selection screen, meaning the game is a collection of mini-Metroidvanias, which still qualifies.
2) Progression through the world is achieved by collecting upgrades to the playable character's abilities which enable said character to overcome obstacles and open up paths to once-unreachable areas. Sometimes simply defeating larger enemies and solving a puzzle with one's wits allows such progression, and some of the upgrading can - but doesn't have to - be according to an RPG system of statistics, accessories, weapons, and attacks.
While in this Metroidvaniac's view having a two-dimensional, nonlinear, exploration-rich map should be enough, in the genre it's almost a given that upgrade-collecting is also involved.
What about 3D Metroidvanias? Certainly they have most of the elements of the genre - and they do. But the transition from 2D to 3D is game-changing in any case of action gaming, and thus if they are included into the genre there should be a distinction made between them and their flatland counterparts. For the purposes of A Metroidvania Website, only 2D games receive focus.
"What is a name?
But when talking of the style of game, must we use this term - this... this... thing, "Metroidvania"? Not necessarily, as there are other labels for the genre.
Obviously some of these are more pleasing to the tongue than others. There can be no doubt, however, that "Metroidvania" is the most effective for indicating exactly what it is one's talking about to a wide expanse of gamers in just one word.
Your resident Metroidvaniac,