6. System Shock 2
Before Rapture and Columbia there was Tau Ceti, a planet with eggs that infected the spacecraft crew of the Rickenbacker. System Shock plays highly similar to the original Bioshock complete with powers, RPG stat building, and an atmospheric horror vibe. The story is also full of twists and turns as to be expected from a Bioshock game though admittedly not as Earth shatteringly brilliant. System Shock never got off the ground completely but for those seeking a challenge or another Shock game check this hidden gem out. It was arguably held back from PC exclusivity and a steep learning curve that requires an understanding of how to effectively build your skills, otherwise you could back yourself into an unwinnable situation.