Programmers face many challenges while developing an AI character, but one of the greatest challenges is adapting the AI movement and behavior in relation to what the player is currently doing, or will do in future actions. The difficulty exists because the AI is programmed with predetermined states, using probability or possibility maps in order to adapt their movement and behavior according to the player. This technique can become very complex if the programmer extends the possibilities of the AI decisions, just like the chess machine that has all the possible situations that may occur in the game.
It's a huge task for the programmer because it's necessary to determine what the player can do and how the AI will react to each action of the player, and that takes a lot of CPU power. To overcome that challenge, programmers started to mix possibility maps with probabilities and perform other techniques that let the AI decide for itself on how it should react according to the player's actions. These factors are important to be considered while developing an AI that elevates the game quality as we are about to discover.
Games kept evolving and players got even more exigent, not only with the visual quality but also with the capabilities of the AI enemies and the allied characters. To deliver new games that took into consideration the player expectations, programmers started to write even more states for each character, creating new possibilities and more engaging enemies, implementing important allied characters, which meant more things for the player to do, and creating a lot more features that helped redefine different genres and created new ones. Of course, this was also possible because technology kept improving, allowing developers to explore even more artificial intelligence in video games. A great example of this that is worth mentioning is Metal Gear Solid, the game that brought a new genre to the video game industry by implementing stealth elements, instead of the popular straightforward shooting. However, those elements couldn't be fully explored as Hideo Kojima intended because of the hardware limitations at the time. Jumping forward from the third to the fifth generation of consoles, Konami and Hideo Kojima presented the same title, but this time with a lot more interactions, possibilities, and behaviors from the AI elements of the game, making it so successful and important in video game history that it's easy to see its influence in a large number of games that came after Metal Gear Solid:
