The starship USG Ishimura sends out a distress signal to the Concordance Extraction Corporation during a mining operation on the planet Aegis VII. Another ship is sent to investigate the causes of the signal; however, as it attempts to dock with the Ishimura, it crashes into it because of a system malfunction. The crew is attacked by terrifying monsters. Only three people survive, among them an engineer named Isaac Clarke. It looks like the ship is barely able to sustain its existence, many of its systems critically damaged. Isaac is the only one who would know how to fix them, and his two companions send him on a mission to find out a way to bring things back to normal and discover the truth behind the horrible events.
Dead Space , a third-person sci-fi shooter with survival horror elements, follows Isaac as he explores the ship, fighting reanimated corpses known as Necromorphs. Combat relies on "strategic dismemberment", forcing players to cut off limbs or parts of the Necromorphs to defeat them. Wounding specific areas can change attack patterns or make enemies more dangerous.
Many weapons in the game are improvised mining tools, such as a rotary saw, plasma cutter, and hydrazine torch. These tools feature secondary fire modes, like rotating the plasma cutter to cut off vertical limbs. Isaac also has special abilities, including slowing down enemies and picking up items from a distance. Certain sections allow Isaac to float in zero-gravity environments. Ammo and tools can be found during exploration or purchased at automatic shops on the ship. Workbenches can be used to upgrade Isaac's weapons and armor.