Space Siege is, as you may have guessed, another action RPG from Gas Powered Games, makers of the Dungeon Siege games (among others). Its score on Metacritic is 60/100, and I have to say that feels about right. It has few glaring deficiencies, but neither does it particularly excel. The dialogue is awful in places, but the voice acting is convincing, and I'm pretty sure I recognized David Hayter in a supporting role. Holy crap, Snake is a starship technician now?! The in-game map deserves special mention for being mind-bogglingly useless. The levels invariably have a significant vertical component, but the 2D map completely fails to indicate this in any comprehensible manner. On the upside (maybe?) the levels are extremely linear, so as long as you keep moving forward it's hard to miss anything.
Space Siege is surprisingly Shadowrun-like in one particular: as you progress, you have the option of installing cyberware into your body. Doing so decreases your "Humanity" stat. I'm not sure what this accomplishes, however; even with all the upgrades, you can't get less than 5% Humanity, so it's not like you're ever forced to choose between implants. I think the ending changes depending on how much Humanity you have left, but I've only seen the full-cyber ending. In any event, cyberware offers so many advantages (and certain implants are required to use the two best weapons in the game), that I really can't see why you wouldn't take the implants.
The plot borrows shamelessly from System Shock 2, to the point that if you've played that game, Space Siege will hold no surprises for you. Pity the gameplay isn't up to System Shock 2's standard.
Bottom line: If you're looking for a Diablolike in a sci-fi setting, Space Siege is worth the $5.10 it's currently going for on Steam. Otherwise, don't bother.