The use of computer games as testbeds for research projects in the Artificial Intelligence (AI) field can be considered as some kind of tradition. Some classic board and card games such as Go, Chess and Checkers were and are extensively used. However, AI researchers are beginning to explore the use of real-time, commercially-exploited interactive computer games in their research, making this a very interesting research field to experiment, and to explore the limits and the possibilities of some AI techniques. Interactive computer games can provide the robust environments researchers need to focus on intelligent agent research. This paper presents the research work that has been developed in our group: the SCORE project (Simulator for COgnitive agent's behavioR), where we use a Belief-Desire-Intention (BDI) agent specification formalism (associated to X-BDI and E-BDI tools) applied to an interactive computer game environment called Unreal Tournament (UT). This paper also presents some aspects regarding agent technology applied to interactive computer games. We emphasize in the application of cognitive agent modeling applied to game characters. The focus is not only to contribute for the game industry itself, but mainly to evaluate the potential of these technologies to solve problems related to user modeling, specially in applications where user's behavior modeling is needed.