3. Dead Space… was original a System Shock sequel
Far, far away there exists an enigmatic mausoleum filled with monsters, and the only evidence of what happened is in audio logs scattered around the world. This narrative could, realistically, describe three different games: System Shock, BioShock, or Dead Space. While it's well-established that BioShock was made as a spiritual successor to System Shock, a lesser-known fact is that Dead Space was, at one point, supposed to be an actual sequel to Looking Glass Games' 1999 sci-fi shooter.
In 2006, EA’s Redwood Shores studio was rumored to be working on System Shock 3, but after the publisher found that it couldn't legally publish the game (they owned the name, not the development rights), the team was forced to make an original IP instead. So they went back to work and made Dead Space, a game that takes place far, far away, in an enigmatic mausoleum filled with monsters. Oh, wait.