DOI: 10.1145/973801.973818The development of interactive, participatory, multisensory environments that combine the physical with the virtual comes as a natural continuation to the computer game industrys constant race for more exciting user experiences. Specialized theme parks and various other leisure and entertainment centers worldwide are embracing the interactive promise that games have made users expect. This is not a trend limited to the entertainment domain; non-formal learning environments for children are also following this path, backed up by a theoretical notion of play as a core activity in a childs development. In this article we explore a central thread in learning, play, as well as an essential characteristic of virtual reality environments: interactivity. A critical review of examples of immersive virtual reality worlds created for children, with particular attention given to the role and nature of interactivity, is attempted. Interactivity is examined in relation to learning, play, narrative, and to characteristics inherent in virtual reality, such as immersion, presence, and the creation of illusion.