Machocruz
Arcane
Not metroidvania, but I'm enjoying the labyrinth of Rain World. Unlike 99% of those games, they didn't phone in the level design. And I feel it's a true heir to the theme and atmosphere of the original Metroid and SM moreso than the straight clones and wannabes; isolation in a hostile, alien, labyrinthine world has rarely been rendered as evocatively in a side-scroller. Abusive and often fiddly game, but utterly compelling, full of vision and craft.