As an initial channel for users learning about a mobile game, the interactive experience of the navigation interface will directly affect the first impression of the users on the game and their subsequent behaviors and willingness to use. This study aims to investigate players' visual attention mechanisms of various interactive levels of mobile games' interfaces under free-browsing and task-oriented conditions. Eye-tracking glasses and a questionnaire were used to measure the interactive experience of mobile games. The results show that in the free-browsing condition, the fixation count, saccade count and average saccade amplitude can be used to reflect and predict the interactive experiences of mobile games' navigation interface; while in the task-oriented condition, the fixation count, first fixation duration, dwell time ratio and saccade count can be used to reflect and predict the interactive experience of mobile games' navigation interface. These findings suggest that apart from the different eye movement indicators, players' motivations should also be considered during the process of the games' navigation interface design. Appl. Sci. 2019, 9, 3242 2 of 15 the traditional measurement methods, such as interviews, questionnaires, and focus groups, are too subjective to reflect players' psychological state and perception process when they are playing [8].Since the intrusiveness of continuous measurements may change the state of the game experience, it is difficult to ensure the authenticity of the results at every moment of the experience and think aloud is a typical intrusive measurement technique [9]. Questionnaires and interviews are helpful for overall feedback after the game experience, but they cannot respond reliably and without loss to events and features that occurred a few minutes ago; making the player review their game video attempts to solve the problem of losing experience information. In this way, the player can think aloud during the review. This technique helps to understand the player's cognitive processing and preferences but it cannot grasp the player's behavior and emotional reactions [10]. A fundamental problem with these linguistic measurement methods is that the emotional experience is not primarily language-based and translating emotional experiences into language requires cognitive effort that may affect measurement.Some scholars have tried to adopt biometric methods to measure players' emotional processing during their playing [11][12][13]. These methods provide designers with players' real-time emotional responses to the game's functionality and design. Moreover, the biometric methods are not invasive and allow the game to be played without disruption. Accordingly, biometric methods, including eye movement, heart rate, blood pressure, facial muscle activity, and brain imaging, are widely used to measure people's emotional responses. In this case, the effectiveness of software interface design can be assessed by monitoring players' physiological activities generated from browsing/u...