A "prototype game" is an early version or model of a new game that is made to test its ideas and mechanics before the final game is developed. Full definition
Students will make multiple smaller prototype games in order to better understand relationships between design, technology, and the resulting player experience. (tag.hexagram.ca)
Besides finding a community of like - minded game developers, jams allow youth to form teams and rapidly prototype game ideas. (gameeducationpdx.com)
Students in the class produced prototype games for the Playstation Vita, and some even went on to work as interns at Sony, eventually getting hired. (the-games-blog.com)