This paper describes an approach towards automating the identification of design problems with three-dimensional mediated or gaming environments through the capture and query of user-player behavior represented as a data schema that we have termed "immersidata". Analysis of data from a study of an educational computer game that we are developing shows that this approach is an effective way to pinpoint potential usability or design problems occurring in unfolding situational and episodic events that can interrupt or break user experience. As well as informing redesign, a key advantage of this cost-effective approach is that it considerably reduces the time evaluators spend analyzing hours of videoed study material. Categories & Subject Descriptors: H5.2 [Information Interfaces and Presentation]: User Interfaces - Evaluation/methodology; H3.3 [Information Storage and Retrieval]: Information Search and Retrieval General Terms: Human Factors