One thing I noticed playing Alien Isolation was its unpredictability. Multiple replays showed the alien and other characters never did the same thing twice, which is entirely the point, explains creative lead Alistair Hope.
"We realised early on that if you could learn its behavior then it would stop being scary," explains Hope. "Hopefully you won't see any patterns because there aren't any". In my case that meant a few tense replays of a corridor section - patrolled by looters while the alien was... somewhere - that never played out the same way twice.
"We realised if you could learn its behavior then it would stop being scary. You won't see any patterns because there aren't any."
I died three or four times in the same stretch of corridor (hard to tell whether it needs better balancing or I was just rushed from demo time constraints) but it gave me an interesting perspective as I watched different hells break loose from the same locker hiding place. Something else happened every time: the alien ran left, people ran right, there was screaming I couldn't see, a man was picked up and his face bitten off in front of me. At one point the creature came right up to the grill forcing me to pull back on the pad and press buttons to hold my breath. It was all very varied and unpleasant.
The result was that outside of the locker, even on a third or forth replay, every step felt like the one that could kill me. As much as I loved Outlast (a game this plays a lot like) enemies settled into avoidable patterns all to easily, something that killed the tension as they dutifully patrolled invisible tracks in the floor. That doesn't seem to be the case here. "The joy for us is that you die, start again and it's like playing for the first time: you can't predict anything," explains Hope. "I think that's where a lot of the tension comes from. You always have to be on your toes".
But how does it work? How do you create a monster that isn't predictable? "I don't want to go too much under the hood because I think that might spoil some of how it might work," says Hope, immediately dampening my plans for a flow chart and a demo with pens on the table. "There's a number of things going on but there's no script, there's no pattern. The AI is just using its senses of sight and sound. When the alien is in a space it tries to find you or anything else it thinks is around. It's not completely black and white. It's not simply 'I can see you/I can't see you', it becomes suspicious of things, so there's an element of grey. It will go and investigate but then if it doesn't find you it will potentially go in a grate and travel through the world and appear somewhere else to investigate".
It makes an interesting gameplay experience because none of the level feels safe - no rooms you know you can't be attacked in, no guaranteed bolt holes. At one point I was yanked up into an overhead air vent without warning. The motion tracker constantly pings out warnings. There are distant hisses, occasional shouts and sometimes the popping of metal panels as if something's moving through the roof space. There's a hint of Slender to it all: at any point you could look around and see the one thing you don't to. The nearest I got to nurturing a sense of safety was getting a feel for reading the motion tracker and having fragile confidence in using crouch to remain unheard.
"We create a space and structure but what happens in that space is quite emergent, it's down to what the player does"
The sense-based AI means things rapidly become unpredictable. At one point I was seen by another survivor who started shooting at me, a noise that was bound to draw the alien. I hid just as a familiar screech came from the dark and when I peeked out everyone was dead. "We create a space and structure but what happens in that space is quite emergent, it's down to what the player does," explains Hope. "The humans and androids, they're using the same core AI [so] they're sense driven as well and things can rapidly get out of hand. I think that's the interesting thing about the other elements: the alien combined with the humans combined with the synthetics - there's some really interesting mixes that just occur naturally and occur in different ways for everybody".
At the moment that chaos and unpredictably feels like both Alien Isolation's biggest strength and weakness. On the one hand the stress of never feeling safe creates a straining, gnawing dread as you poke fearfully through dark corridors. But it can also be frustrating. The corridor part of the demo I played saw numerous restarts as unexplained alerts and unpredictable outcomes seemed to wrestle control of my fate away from me. It might be realistic but it's not always fun. The atmosphere's a documentary level recreation of the film however and if Alistair and Creative Assembly can nail an AI balance that captures the original's haunted house scares without feeling unfair then this is going to a very special horror game.