With the spread of interactive narratives in computer games, the issue of analyzing the structure of these narratives in terms of user agency has become one of the emerging areas in game studies and narratology. The aim of this research is to analyze the structure of interactive narratives in computer games, focusing on user agency; in particular, how this agency is embedded in the narrative structure and how its different levels can be classified. This research was conducted with a qualitative method based on narrative analysis and through direct observation and content analysis of selected games from the last three console generations, the narrative structure of games was measured based on five components. Based on a conceptual framework consisting of interactive narrative theories and game design, five key components were extracted: frequency and quality of decision points, control of the main plot, the range of impact of embedded choices, the complexity of story details, and the range of narrative consequences. These components formed the basis of a four-layer classification that distinguishes interactive narratives from minimal to maximal. Analysis of the samples shows that there is a significant relationship between different levels of agency and the complexity of narrative structures. In maximal narratives, user agency is effective not only in minor choices, but also in redefining the story path, endings, and even organizing the game world; while in minimal levels, agency is limited to superficial and low-impact choices. By proposing an analytical model, this research provides the possibility of measuring and comparing levels of agency in narrative games and can be a theoretical basis for designing or analyzing interactive narratives in future studies.