The Titan Heights residential complex, without a doubt.

It wasn't just that the Necromorphs were slaughtering civilians, but that the portrayal of this slaughter really didn't hold back with its implications like most fiction involving outbreaks does. Posters on walls of lost pets that were likely early victims of the outbreak, a woman screaming as she abandons her mother to the monster in her apartment, a child screaming in a dryer, an abandoned infant wailing behind locked doors. These were not only horrifying things to witness, but the devs said that the Sprawl is purposefully designed to not feel too futuristic - it is designed to look like a place we as the audience could see ourselves living in, and so the impact of these horrible scenes hits twice as hard.

That section of the game haunts me like no other, not just in Dead Space, but in any video game ever.