Dead Space 2 is a survival horror third-person shooter. The player controls Isaac Clarke from a third-person point of view, looking over the character's right shoulder. The game features no HUD, relying on holograms projected from the player character and his weapons to show information such as messages and ammunition count, respectively. Player health and stasis are shown by visual indicators on Isaac's back. Isaac must fight an alien organism that infects and takes control of human corpses, turning them into "Necromorphs", mutating their bodies. Necromorphs must be dismembered as the alien organism controls host bodies via tentacles extending into their limbs. Other, larger types of Necromorphs that cannot be dismembered will often have yellow, glowing pustules, indicating weak spots. Occasionally, when an enemy gets close enough to Isaac, they will grab a hold of him, and the player must repeatedly press a key to fend off the enemy, with failure to do so leading to death of the player character. The player acquires two modules; a "stasis" module, allowing the player to slow down enemies or objects, allowing for otherwise insurmountable moving obstacles such as active heavy machinery to be slowed down, allowing Isaac to safely pass, and the "kinesis" module, which allows Isaac to manipulate objects, machinery, and panels obscuring important circuitry, which Isaac can then tamper with in order to open doors and gain access to otherwise restricted areas.
The player may upgrade their weapons and armor at work benches, using nodes found throughout the game. In-game stores may be accessed where the player may buy and sell various items and attain new weapons and suits.
The player encounters zero-G environments, where Isaac is capable of maneuvering with thrusters attached to his suit.
Dead Space 2 offers five difficulty levels; Casual, Normal, Survivalist, Zealot and Hardcore. Hardcore mode is unlocked once the game has been completed. Hardcore mode can only be played from a fresh start and the player is limited to three saves in the entire game, with ammunition, health, supplies and credits being very difficult to find, and enemies are very challenging. There are no checkpoints in this mode.