Artificial intelligence (AI) is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its chances of success.

With AI  games appear to be more realistic.

Further ideas & AI implementation:

 AI 4 Programmers: Brian Schwab, AI Game Engine Programming (Book & Source)