If a Metroidvania was set in the world of Bioshock? Kind of maybe?
The Aquatic Adventure of the Last Human is a pretty straight-forward journey through the flooded remains of Planet Earth, but it's incredibly satisfying. It scratches a bit of the Metroid-Vania itch, but in a more streamlined fashion. It's mostly about the boss fights and damn if they aren't cool! Figuring out how your lackluster arsenal will function against certain bosses is a treat, albeit frustrating at times. Each time I see a room that looks like a boss room, I am overcome with dread for a moment, only to then steel myself and prepare for the fight to come. It's a fun challlenge that requires skill but also presence of mind.
The game is mechanically sound, and while there are some restrictions early on that don't seem to make sense at first, it soon becomes clear the developers had to leave room for progression.
The real achievement, in my opinion, is the visual and sound design. I absolutely love the look of it, even though the popular consensus about pixel art, seems to be that it's overdone. In the case of this game, it still feels new and fresh and manages to give depth to the environments as well as the boss fights. The wildlife and underwater flora simply look fantastic.
Lastly, the sound design of the game is very interesting. Some sounds are a bit odd, but the underwater atmosphere is oppressive but also comforting at times. The sometimes soothing, other times unnerving sounds of the deep really add depth to the environment. In addition, the musical soundtrack is just perfect for the game, each "district" having its own song.
Overall, this is a fantastic game you should definitely play!