Computer gaming is one of the main branches of computing today. For providing optimum experience, the developers have leveraged many different technologies into computer games. With the emergence of artificial intelligence, game developers adopted it for making games more realistic and closer to the real-world environments. Non-player characters play a crucial role in providing immersive experiences for gamers. This article presents the results of a systematic literature survey conducted on the role of artificial intelligence and machine learning on the creation of intelligent non-player characters. Along with the results of the survey, this article also presents the current status and the possible future directions for this research domain.