Just in case I’d not had enough Metroidvania games, I bought another one. Only this one is underwater!
Which means you constantly have to look for oxygen, and being attacked drains your oxygen, and jetting around drains your oxygen, and you move slowly and you have a harpoon. And at one point you gain use of a hovercraft cowfish shaped submarine which means you don’t need oxygen when in it, and – more importantly – you can survive deeper water. One of the main mechanics is that your suit can only deal with a certain amount of water pressure. Go deeper and you quickly die, but you can keep upgrading it to allow deeper exploration with the right resources.
Which is another “difference” with this Metroidvania. You get items mostly from mining rocks and collecting plants, rather than defeating baddies. Combined with the suit and floaty physics it certainly doesn’t feel like just another Metroidvania (not that I’d complain if it did, see previous entries on this blog!) but it is. There’s also two separate endings depending on how you deal with the end boss – I got both.