Visual program simulation (VPS) is a new, interactive form of educational program visualisation, in which learners use graphical controls to direct a program's execution rather than simply watching an animation of it. In this article, we report on a qualitative empirical study of novice programmers learning through VPS. From an analysis of interviews with learners and supplementary observational data, six different ways of perceiving learning through VPS emerged. While a rich understanding of VPS opens up rich possibilities for learning programming, we also uncovered several ways of understanding VPS that do not afford such opportunities. For instance, learners do not always attribute meaning to the visual elements, and even when they do, they may fail to associate the visualised concepts with programming practice. Our results concretise how learners have to experience a number of key insights "about" VPS before effective learning "through" VPS can take place. Based on our findings, we make pedagogical recommendations with the overall goal of improving the integration of VPS and the rest of the teaching and learning environment. Our results may find applications beyond VPS within educational program visualisation in general.