Whilst the use of documentary film to mediate issues of international development and social change is nothing new, the tools of production, media environment, expectations of, and relationships between, audiences and content are evolving at a rapid pace, bringing new approaches and challenges. As INGOs, development agencies and media producers attempt to engage audiences in issues of international development and social change in an increasing saturated media environment, many are looking for more innovative, Web 2.0- native ways of presenting these issues. Interactive web documentary, a format that has emerged from the dynamic and frenetic Web 2.0 media environment, combining digital, interactive and social media with the documentary form, has begun to be used to communicate with and engage audiences in these issues. But how do audiences respond to this format? Within this paper I investigate, through a survey of three audience groups and two case study examples, supplemented by semi-structured qualitative interviews and focus group discussion, how interactive web documentary might affect audience engagement with issues of international development and social change. In so doing I uncover three modes of engagement: active engagement, emotional engagement and critical engagement, which appear to be enhanced by the format. At the same time I discuss barriers to engagement, such as access, audience interest and tensions between discourses of gaming and issues of international development and social change, all of which must be negotiated if the format is to succeed in its aims.