"The year is 2047... oil has run out... governments have collapsed." It all sounds a git grim in the future. That probably explains why people are going underwater to have third -person battles in suits designed by Master Chief's tailor. Biart7's Deep Black: Reloaded is available on Steam right now for £18:39/$23.99, or on the official site for £15.99. There's also a 432MB demo available for download.
We haven't played this yet, but there's certainly potential for some fun wet/dry shooty action, even though there's no multiplayer. You might want to dust off the Razer Hydra if you've got one too - Deep Black supports the quirky little thing.