The project team is developing and testing a prototype of PiGames, intended to be a game-based formative assessment system for physics. The prototype will include a curated collection of pre-existing assessments, authoring tools to create new assessments, a dashboard with progress monitoring, and teacher implementation support. In the Phase I pilot research with 6 classrooms and 180 high school students, the team will examine whether the prototype functions as planned, if teachers are able to implement it with students, and whether students are engaged.