Metroidvania?

[Angry Video Game Noob]

Or just another boring platformer with no content at all?

[Penguin]

I'd go with boring platformer with a moderate amount of content.

[Geekfox]

Capsized is a non-linear platformer, but not fully metroidvania.

There's dozen stages you complete in order — there's no backtracking, and inaccessible sections (that would require upgrades) are non-existent.