Many of the horrors you’ll encounter in the Dead Space series stem from the Marker, an alien artifact that has the remarkable ability of being able to slowly drive people insane. Spend too much time around it and you’ll suddenly find yourself battling the urge to embrace your inner Necromorph and brutally maim everyone around you. This is really only teased in the original game, as you see the aftermath of what happens when a group of people stick around a Marker for too long. It’s not until the sequel that we get the chance to witness the transformation firsthand.
In Dead Space 2, Isaac begins to fall under the Marker’s influence. This results in horrific visual and auditory hallucinations, many of which that feature his dead girlfriend, Nicole. But the reason Dead Space 3 makes this list over its predecessor is the way this sanity system is woven into the game’s co-op. Both Isaac and his new “friend” Sgt. John Carver are being affected by the Marker, and this results in separate hallucinations for each player. So what you see on your screen might not necessarily be the same thing your partner is looking at.
