Artificial Intelligence

     After Half-Life is released, other game companies will no longer be able to put just a little time into AI like they currently do. Steve's goal with Half-Life's AI is not enemies that can out maneuver and hit you no matter what you do. The goal is AI that gives the feeling of a real environment. From what I have seen, this helps the suspension of disbelief, throwing the player further into the game's world than anything previously seen. Creatures act like they are a part of a real ecosystem.

     The alien creatures certainly do not like you. They may want to kill you, eat you, or turn you into a zombie. This does not mean that they are single-minded drones, though. They may desire other prey or hate other creatures more than you. They may even want fresh meat more than you. This means you can use monster carcasses to distract beasts that would otherwise kill you. This will allow you to safely pass an area that would otherwise be your grave.

     Not only is there good single creature AI, but there is group or pack AI as well. One example Steve showed me involved the houndeyes. In case you are not familiar with them, the houndeyes are relatively small, three legged creatures that attack, not by chewing on you or shooting projectiles, but through a piercing sonic attack. Houndeyes usually travel in packs, with one houndeye obviously taking the role of leader. The leader usually stands on his hind leg, constantly watching over the rest of the pack and watching the environment for danger. You can stand there and watch them from a distance without fear of an attack. The others in the pack will continue to forage for food while the leader will warily watch your every move. Wander too close however, and the houndeyes are no longer docile-looking creatures, but a vicious threat to be taken seriously.

     As you see and hear their attack, cries that cut through to the bone will start tearing you apart. Your first instinct is to run to safety. A corner-shaped brick wall is nearby so Steve starts heading for it in an attempt to find safety. Seconds later, one of the houndeyes shows up. One houndeye is not a particularly difficult adversary, but there is something you do not know. Instead of facing the houndeye, you choose to flee the other way out of the area. What you did not realize is that when one houndeye finds you, he communicates your location to the others in the pack. The houndeyes you did not see figured you might try to escape so they went over to cover the other entrance, stopping you in your tracks. At this point it is fight or become kibbles and bits for aliens. If you get that kind of teamwork and thinking with basic creatures, what could this mean for humans?

     Throughout Half-Life, you will meet both helpful humans and those that are out to erase all evidence that your mother spent hours in labor to bring you into this world. You can kill any one of them but it is not always wise to do so. Among the humans you meet, you will find other scientists that are as confused and in danger as yourself. You can save them from being killed by the other creatures, or you can just talk to them while they are wandering the halls. They can sometimes help make traversing a level easier. You can also have them follow you without too much worry that they will get lost or get stuck at some simple obstacle. I was shown the pathing AI at work. I was told to lead the main character quickly through a maze, up a slope to another level and jump across some platforms. The scientist got to the complicated jumping and was smart enough to know that he did not want to do that so he turned around and found a completely different, simpler way to catch up to where I was located! I had never been that way before either, which made it all the more impressive.

     The military grunts are very smart as well. You may think a government force would be on your side against the aliens. Guess again. I was shown a demonstration in the same room the houndeyes had been in, except this time the room was occupied a squad of grunts in white and black camo gear. The grunts laid cover fire and did not shoot the other grunts by accident when they switched positions. When hit, one of the grunts crawled out of the way to safety behind a wall. Others were good at dodging rather than just standing there to take bullets in the chest. The whole time you can hear them communicating. They will constantly work to get a better angle of attack on you. Outnumbered, I attempted to escape the grunts by running behind the same wall as before. The grunts held back as I popped around and fired a few rounds their way. I stayed back there a little too long though; all of a sudden there was a grenade bouncing off the wall near me and heading my way. I had to clear the area before it went off so I ran the other way in a panic only to find that the grunts had flanked me from both sides. I ended up becoming a lot more transparent as I got filled with lead.

     One other example to show that the environment in Half-Life is indeed realistic: there are even cockroaches in the game with moving antennae and everything. They even behave like real cockroaches! They are photophobic (afraid of light) so if they are in a room munching on food or flesh lying about, they scatter into the corners when lights are turned on. They will also run away from creatures even if the lights are out, but sometimes they are not fast enough and you hear a crunch with the resulting green splat on the ground.