One of the most important features of a (computer) game that makes it memorable is an ability to bring a sense of engagement. This can be achieved in numerous ways, but the most major part is a challenge, often provided by in-game enemies and their ability to adapt towards the human player. However, adaptability is not very common in games. Throughout this thesis work, aspects of the game control systems that can be improved in order to be adaptable were studied. Based on the results gained from the study of the literature related to artificial intelligence in games, a classification of games was developed for grouping the games by the complexity of the control systems and their ability to adapt different aspects of enemies behavior including individual and group behavior. It appeared that only 33% of the games can not be considered adaptable. This classification was then used to analyze the popularity of games regarding their challenge complexity. Analysis revealed that simple, familiar behavior is more welcomed by players. However, highly adaptable games have got competitively high scores and excellent reviews from game critics and reviewers, proving that adaptability in games deserves further research.