Preschool-aged learners process information differently from older individuals, making it critical to design digital educational games that are tailored to capitalize on young children's learning capabilities. This in-depth literature synthesis connects features of digital educational game design - including visuals, feedback, scaffolding challenge, rewards, and physical interactions to how young children learn. Preschoolers' interests and abilities (e.g., limited attention-span, early reading skills, etc.) are different than older users. As such, developmental science should be used to guide the design of educational games from aesthetic decisions that capture preschoolers' initial interest (e.g., meaningful characters) to carefully select end-of-game rewards (e.g., leveling up). This article connects learning and developmental science research to the design of digital educational games, offering insights into how best to design games for young users and how to select developmentally appropriate games for children.