Many of us have had the vision of learners acquiring STEM subject matters by being immersed in motivating learning environments (such as games) that advance learners to new levels of mastery. Concepts in STEM (science, technology, engineering, and mathematics) are complex and difficult, and require learning at deeper levels than merely memorizing facts, rules, and procedures. Learners would ideally be challenged and motivated to improve on mastering complex topics that might not be acquired with traditional training methods. They would spend hundreds of hours in a hunt for a solution to a problem that few have solved, for the sweet spot in a trade-off between two or more factors, or for a resolution to a set of incompatible constraints. This is precisely the vision of progress for training in the 21st century. How can deep learning be achieved in a motivating learning environment? Games provide a good first place to look for answers because well-designed games are motivating and some meta-analyses have reported positive impacts of games on learning (Mayer, 2011; O’Neil & Perez, 2008; Ritterfeld, Cody, & Vorderer, 2009; Shute & Ventura, 2013; Tobias & Fletcher, 2011; Wouters, van Nimwegen, van Oostendorp, & van der Spek, 2013).