The recently confirmed Dead Space 3 allegedly has drop-in, drop-out co-op.
According to an IGN source, series star Isaac Clarke will fight alongside another man, if the player chooses, described as having a "gnarly scar on his face, an engineering RIG of his own, and glowing red eyes peering from his helmet."
During the single-player mode, this character will act as Isaac's guide. The cooperative mode "mirrors" the single-player campaign, but the Isaac's story changes to accommodate it. IGN notes that in the single-player mode, Isaac's partner doesn't show up in some cut scenes. In co-op, the story changes slightly to accommodate the new character.
Players will allegedly work together, using the new and improved telekinesis powers, to interact with pieces of the environment. In addition, you'll be able to share ammo with and heal you co-op partner, although there is no revive system. If one player dies, both players will reload from the last checkpoint.
Dead Space 3, confirmed by EA during its 2012 financial report, is due out on PC, PlayStation 3 and Xbox 360 before the end of the current financial year – that is, before April 2013.