In case's survival horror Alien: Isolation wasn't tricky enough on hard mode, you insane person, you can now try it out on Nightmare mode.
The new setting has been added as part of a free update. There's some good news if you're of a less masochistic disposition though, because it's joined by a new Novice mode.
Interestingly, this isn't just about reducing your health or taking some ammunition away; in Nightmare mode your motion tracker is distorted, meaning its readouts will be unreliable. The alien is tougher and smarter, and the map system is off-line.
Novice mode is a little more traditional, making you more resilient and enemies easier to kill. Which sort of goes against the point of the game, but there you go.
There's a few other changes for both modes, which are neatly summed up over on. The update is available now on all platforms.