The online is kind of useless, but survival horror fans will likely appreciate every aspect of this game nonetheless.
Anyone who appreciated the first Dead Space should love this game without an ounce of hesitation. Every single aspect of the game has been improved upon greatly. You play as Isaac Clarke, currently on a colony on one of Jupiter's moons three years after escaping the USG Ishimura at the end of the first game. He's being haunted by disturbing images of his dead girlfriend, Nicole. The asylum he finds himself in goes to hell as it is terrorized by invading Necromorphs. Isaac knows that the Necromorphs are a product of The Marker, a man-made structure that Unitologists believe to be the "Holy Grail" of their religion. Isaac's goal is to determine what caused Necromorphs to show up in the colony while desperately trying to avoid being brutally killed by necromorphs.
The game is played as a third-person shooter. Isaac's RIG, his suit, protects him and provides him with information and communications with other characters. As the game proceeds, you can upgrade your RIG as well as the weapons in your arsenal using Power Nodes which can be found in many places or bought at stores.
Many of the classic weapons from the first Dead Space remain, ie. the Plasma Cutter, Pulse Rifle, Flamethrower, Force Gun, Line Gun, etc. A few weapons have been added in Dead Space 2. These include the Javelin Gun, which fires a spear that can pin enemies to walls and can also be electrified to damage other enemies near the javelin. There is also a sniper rifle called the Seeker Rifle. The Detonator allows you to place explosive proximity mines. The Arc Welder fires a dangerous electrical charge.
The music and sound design both serve to add helplessness and despair to the atmosphere. It's unfortunate, though, that this game doesn't steer entirely clear of cheap scare tactics, and by that I mean a necromorph popping out of the ceiling right in front of you with a loud violin screech. It's been done many a time before.
The multiplayer isn't that great. It's fun to play as the necromorphs trying to kill humans, but the novelty wears thin pretty fast as you realize the single player is much more fun and immersive.
The story isn't particularly long, clocking in on normal difficulty at about eight hours. It is sufficient, though, because you'll likely be inspired to play through the game at least one more time, whether it be with the retention of your weapons and upgrades from your previous playthrough or without them on a higher difficulty.
In the story, Isaac progresses from locale to locale in the colony. The first game was told in chapters, each one requiring you to disembark the Ishimura tram, complete an objective, and return to the tram. Then a long loading screen would load the subsequent chapter. Dead Space 2 is told in a series of chapters, but the gamplay never stops. There are no loading screens. The action just keeps on coming, giving you barely any time to catch your breath.
It certainly works to its benefit, because once you start playing you're not going to want to put down the controller until you're finished.