System Shock takes place on the Citadel Station, you play as a hacker who was caught trying to get into the Tri-Optium main frame, Captain Diego, impressed with you, allows you to reprogram the ships main A.I SHODAN, and you get a neural interface. Well while your out SHODAN goes off the wall mad and mutates everyone.
Yeah, that's right, System Shock, a shooter from the Doom era. Had an engaging and deep plot.
System shock has great RPG elements. But it has a bit of a learning curve as you try and figure out how the inventory and everything works, but once you do the experience becomes enthralling.
My only real complaint is how disorienting it is. It may just be my eyes being destroyed by the virtual boy but this game is dizzying. Moreso than Marathon. And the cyber space, while inventive, is a bit confusing, but still REALLY cool.
System Shock is a great game, and if you can find it, you'd be doing yourself a favor by playing it.