There have been many other oceanic or undersea exploration games before, but Diluvion still seems like a somewhat unique take on the concept. It combines real-time exploration in a 3D environment somewhat similar to Skies of Arcadia or No Man's Sky, with real-time ship and crew management in a 2D style similar to FTL, and then adds on a number of interesting additional mechanics on top this.
You can salvage parts from downed ships, recruit new crew members from scattered underwater colonies, and you must manage the oxygen and other resources of your submarine while exploring a tale taking place in the ruins of a now sunken civilization, all while making sure that your crew doesn't die.
In a market where most underwater exploration is bright and crystal blue, Diluvion opts for a slightly darker and foggier underwater landscape, which makes anticipating the unexpected a frequent feeling. This leaves you to resort on the sub's sonar ping system in order to get a idea as to if what you're looking at it just a wall, or a gigantic cyborg spider getting ready to laser scuttle you to death.
Diluvion isn't the most unique looking game in the world, but its mechanics seem very solid, and the exploration and art-style are both enjoyable. So keep an eye out for its release if you're looking to plunder undersea treasure later this year.