I hate the word "Metroidvania", but I can see why it's being used so often. The play is very much Super Metroid, with recent 2D Castlevania RPG-ish influences as well. The world and characters are very detailed 3D. It's just the motion path that's restricted to 2D as in the inspiring games. This is disconcerting at first. Example, you see spiral staircases, but you can't use them. You have to hop from ledge to ledge on them instead. Enemies can come at you from any direction, and it seems that since you're stuck on this plane, you can't shoot them. But the game handles that by completely autoaiming along the Z axis. You just have to handle X & Y.
It takes a while to get really good. There's a lot to find which ups the freedom and fun factor. A few things bug me. There seems to be no way to aim diagonally without moving. Missile obstacles are sometimes too close to shoot without you taking damage. I'm having a hell of a time aiming underwater. (This may just be me.) Some hitching can skip a lot of frames, though this is very rare, and seems isolated to a few spots (streaming transitions?). Other than that, it plays beautifully and looks amazing. I love the "Lucent" visual setting in this engine. Well done, Chair & Epic.