Kalonos: They are adventure games in where you explore a map with locked zones looking for upgrades, after which those zones come open. It doesn't need to be a sidescroller to be a Metroidvania game. What are the Metroid Prime games then?
SirPrimalform: 3D first person games with metroidvania aspects. The definition of metroidvania doesn't magically change to accommodate whatever direction the Metroid series takes...
Anyway, you're welcome to call them whatever you want. I was only saying that I certainly wouldn't consider them metroidvanias.
"Metroidvania" isn't a real genre, so I don't why the definition matters. Metroid Prime is basically Super Metroid in 3D: platforming, shooting, nonlinear, open-world exploration, it's all there. Mario 64 is 3D, but that doesn't make it any less of a platformer than Super Mario World.
"Metroidvania" isn't even an accurate term since Metroid is the one started the open-world-platforming-adventure thing, and Rygar predates Castlevania II by several months. "Rygaroid" might be a more accurate term.