When dealing with novel fields of studies that remain unexplored, the Delphi method can be a useful technique. We used it to define and propose a set of criteria by which to analyze communicative and educative features of online climate change games. The method allowed us to collect opinions of experts in a structured and interactive way, reaching common consensus. In our case, three consulting rounds with experts were enough to reach agreement among experts on the final set of criteria. We started with an open approach in the first round and ended up using a closed questionnaire. In this case study, we address the researchers' experiences, as well as the benefits and challenges of this method.