Metroidvania

The Castlevania games share similarities with the Metroid series, in particular the free-roaming design in which new abilities allow access to different areas. Because of this, fans often refer to such games as “Metroidvania” in style.

It's got Metroidvania elements - it's structured like one, I guess, in that it's lots of exploration with a fair bit of backtracking and getting new abilities that unlock previously unopened areas and that sort of thing.

Pure Metroidvania... with 3D in-engine cutscenes.

Metroidvanias are an inherently clever genre, and the cleverness can sometimes sap a little of the energy.