When scientists need to record signals from human participants such as their eye movements or their brain activity, they need to ask them to physically come to a research facility. This process is costly and time-consuming. As a consequence, the human sample size in a typical neuroscience paper is below 100, and the cohort often consists in students from the local university. Here, we argue that video games can be a useful and cost-effective solution to drastically increase the sample size and diversity of human-based experiments. We developed Sea Hero Quest, a mobile gaming app that records users’ spatial exploration strategies. The game has been downloaded 3.7 million times in every country in the world. We are using these data to create the world’s largest benchmark of how humans navigate, which will then go on to become a critical diagnostic tool for dementia in the future.