This article takes its point of departure in the research methodology of a comprehensive and multi-disciplinary innovative intervention study in Swedish preschools with preschoolers aged 3-5, involving two digital learning games focusing early math and executive functions. Based on a combination of video-ethnography, focus groups, field notes and digital progression log data, the analysis of a pilot study of the pedagogical intervention challenges and extends theoretical and methodological perspectives on what it means to undertake an intervention study in this context. The aim is to discuss what a mixed-methods research approach may provide for the understanding of intervention methodology by illustrating how different types of data provide understandings of how and to what extent the intervention components are functional in the pedagogical setting. The conclusion the analysis supports is that unless children's and preschool teachers' meaning making of the unfolding actions in the digital interface make them engage in the activity and dynamically fits within the institutional preschool system, the intervention will not be functional. A pilot study can provide detailed understandings of why, how and in what contexts interventions as part of the dynamic preschool systems can be implemented with adherence and fidelity.