There's a lot to like about Hostile Waters. It's an innovative and unique blending of strategy and action, with a decidedly original storyline penned by one of the best writers working in comics today, Warren Ellis. The basic premise is this: global peace has finally been managed. The war machines, weaponry, and soldiers of the bad old days are decommissioned or destroyed. Only....not everyone was looking for peace. And a few of the hardliners have come out of hiding and launched a terrorist campaign to which the world is now defenseless. Or almost.... there's one of the old school nanowarfare carriers left, a mobile weapons factory known as Antaeus. It's been submerged and abandoned for some time, and the first few missions of the game deal with collecting the resources necessary to restore full operations. The Antaeus, when given the blueprint and enough fuel, can synthesize any vehicle or weapon necessary for the conflict. You are in charge of the Antaeus.
You get a wide array of vehicles to throw at your foes, and while you can pilot them yourself directly (thus the action part of the game), you will usually want to load them up with a personality chip taken from one of the soldiers that fought in the last war so that they can move about autonomously (under your orders, of course). Each soldier has a different personality and skillset, and as you find them you learn more about their history in cutscenes. The enemies themselves constantly regenerate until you can find and destroy the factories producing them, and there are often other story-related goals.
All this makes for a game that I for one have found extremely compelling, and paying $6 for it almost feels like stealing. Note that the boxed copy has a bug which fails to recognize the retail CD, requiring a no-CD patch to play the game at all. So even if you have a chance at the box, I'd still recommend this version. Saves hassle.