By Ujaan Pal Chawdhury
We accept many elements from a game and much of which is quite achievable such as photo-realistic visuals, ray tracing, virtual reality, but sadly a good AI(Artificial Intelligence) in a game is not always mentioned in the list nor is appreciated as much as the other elements. Surely, the Artificial Intelligence systems associated with titles like ‘GTA’ and ‘Just Cause’ are sometimes dumbed down on purpose for the players to have fun with the Non-player characters of the open worlds. But when it comes to the smart implementation of AI’s for NPCs in gaming, the Xenomorph from 2014’s survival horror title Alien: Isolation takes the top spot.
The game puts you in the shoes of Amanda Ripley, daughter of the iconic Ellen Ripley from the movie franchise, who tries to survive in a space station with a Xenomorph on the loose and relentlessly hunting her down. Frankly, the Xenomorph becomes the true star of the show. Firstly for its menacing design taken directly from the movies and secondly, for the wonderful AI pulling its strings.
The AI implemented for the Xenomorph is layered, where two parts of AI, macro and micro are always functioning together simultaneously. The macro AI directs the Xenomorph in the approximate direction of the player but never tells the player’s accurate positioning. This is where the micro AI plays its part. It controls the Xenomorph’s behaviours such as patrolling an area and checking different hiding spots. The entire game is overseen by the macro AI which maintains a menace gauge to keep track of the player’s actions and guide the Alien accordingly.
When the menace gauge is low the Xenomorph will look for the player, and the gauge increases when the player comes in close proximity to the Alien. When the gauge reaches maximum the macro AI directs the Xenomorph to go to some other place to provide relaxation for the player and to make the game progress fairly. Unlike other games where NPCs spawn at given locations, the Alien here physically travels from one point to other instead of just teleporting to the player's location. This is a key feature used by the developers to keep the game balanced.
It should also be mentioned that being a survival horror game, your options to fight the Alien is extremely low as the Xenomorph can one-shot you. So the only option for the player throughout the majority of the game is to run and hide. However, there is a catch. The micro AI is actually adaptive; meaning, it studies and remembers the players’ actions. For example: during an encounter with the Alien, if it sees you leaving or entering a hiding spot such as a locker, from the next encounter onwards the Xenomorph will begin to check other lockers.
All these gameplay factors might seem overwhelming for the players but the game plays quite fair. Alien: Isolation offers a challenging blend of horror, stealth and probably the smartest enemy that gaming has to offer. Alien franchise’s previous game, 2013’s Aliens: Colonial Marines, was criticized for its horrendous AI, later revealed to be caused by a single typo. Ironically, with Isolation, the same franchise created a landmark game using brilliant AI work, just a year later.