You may think that having a whole, sprawling space station inhabited by Necromorphs would be scary. Or the fact that old Isaac is now a complete mental case. Or the way they introduced multiplayer. But while all these things were pants wettingly scary, nothing came close to the horror of having to carry out a bit of DIY surgery involving a futuristic laser machine. You needed pinpoint precision to guide the beam right into the centre of your iris and - believe it or not - it did serve a purpose: to activate the part of the brain affected by The Marker. Just don't miss.