While in many ways Dead Space 2 is a rinse and repeat of its predecessor, there have been several new features added to keep things fresh. In addition, this game is much more PC and keyboard/mouse friendly, lacking the mapping and control problems of the first game. I also like that the developers have given Isaac Clarke a face and a voice, which I think gives the player a stronger identity to relate to.
As to the story, it picks up three years later and begins with the discovery that Isaac is institutionalized on the Sprawl, a highly populated space station surrounding one of Saturn's moons. Having been rescued when found drifting in space near Aegis VII, where Dead Space ended, Isaac is apparently suffering from memory loss. The game opens with quite a bang when during a session with one of his doctors, a sudden Necromorph outbreak throws the player into instant action. With Isaac constricted by a straight-jacket and weaponless, he needs to find an escape route through the chaos breaking out on the station. However, once he reaches relative safety, a woman named Daina Le Guin contacts him via radio communications and fills in some of the missing history. When Isaac was first found and examined, it was discovered that his previous contact with "the marker" had left a life-threatening signal imprinted in his mind. The administrator of Sprawl, Hans Teidmann, decided to administer memory-suppressing drugs to keep it in check. Daina claims to have a cure for Isaac and reaching her is the goal of the first few levels of the game. When accomplished, Isaac further learns that Teidmann used him while in this amnesiac state to replicate a marker on Sprawl. For the balance of the game Isaac's mission is to destroy the thing he unwittingly helped to create. Throughout it all, he is plagued by hallucinations of his dead girlfriend Nicole from Dead Space.
After the initial excitement of the opening, this game takes quite a few chapters before really picking up steam, but it does get more intense after the first half. I wasn't overly impressed with the level designs in the beginning either, but again, this was much improved upon later. Poor Isaac - the developers certainly throw some nasty situations at him, for instance, forcing him through a daycare center is a bit disturbing as you can well imagine. It's a dark story in some ways, using morphed babies and children, but I suppose realistic in its way. Some of the cut scenes are also designed to get your blood pumping by integrating some interactive portions. A few more devices besides spawning Necromorphs are used to surprise you.
Much of the Dead Space game mechanics return. We have basically the same choice of weapons with a couple of new ones, upgraded armor, stasis, telekinesis, credits, nodes, upgrade benches and stores. I would say, however, that some of these things are not quite as plentiful and that stasis has become a lot more imperative for survival. On normal the game can be quite hard at times and Isaac still has a fairly slow recovery rate after a direct contact attack with the Necromorph. There are also no air canisters in this game and no map, although we still have the locator. There doesn't seem to be as many nodes either, so that on first playthrough you have to be very choosy about what to upgrade. It's possible to get caught with the wrong weapons during the final boss fight, making it much harder.
The Necromorphs are basically not much different either and you still kill them by shooting off their limbs. Unfortunately, later in the game, the shortness of nodes doesn't allow for upgrading all four weapons, your rig, and your stasis to max, leaving them not quite as effective on first playthrough. There are also limited locations for stores and upgrade benches. Manual saving at specific checkpoints remains the same and with the same limited save spots so that you will have to overwrite. But be sure to keep the "clear game" save at the end if you want to replay with your upgrades.
The environmental graphics are pretty good, but even though I love the addition of getting to see and hear Isaac, the character rendering isn't always top notch. At times, Isaac looks like a wax doll and once, when he emerged from upgrading his suit, he had seriously changed skin color. Sound level was another problem in places. Nicole frequently speaks and whispers to Isaac and I found it very hard to understand anything she said. I also found that the keyboard buttons sometimes didn't respond and needed more of a pressing than a quick tap. This, of course, can get you killed in tight situations. Quick stasis can only be filled when your not aiming and this button also needs to be pressed for a few seconds. Aiming is vastly improved as is getting around in zero gravity. Stomping Necromorphs is a load of fun and if you do it long enough you will hear some choice comments from Isaac.
Due to an outcry about the free DLC not being available to the Steam PC version, it was patched to automatically integrate it into the game. The DLC gives you zero cost items in the store as well as new items. Many players hate this for a first playthrough and it can't be disabled. Other versions, though, allow you to patch in the DLC later, so you may want to consider where you make your purchase.
Dead Space 3 is on the horizon and will feature a new co-op mode but no multplayer.