Overall, game-based technology for early reading instruction has not robustly met the learning potentials of young readers. To better understand the effects and limitations of computer-assisted instruction in classrooms, researchers have called for more critical attention to learning theory, methodological selection, and context for learning. GraphoGame (GG), an adaptive serious game designed to prevent reading difficulties through the promotion of sound--symbol connections, has been implemented in over 20 countries. Therefore, the GG research base provides an opportunity to synthesize research on a single computer-assisted instruction across diverse contexts. Surprisingly, despite extensive use and further implementation plans, no review has yet synthesized GG's effects. Specifically, this systematic literature review, with an embedded meta-analysis, synthesized 28 empirical studies for theory, methodological quality, and outcomes. The GG research base was dominated by theories of reading disabilities and psycholinguistics. Methodologically, quantitative methods, focusing on phonological and decoding outcome measures only, were most common. The meta-analysis (n = 19), measuring GG's impact on word-reading outcomes, did not yield an overall meaningful effect size (g = -0.02). However, among moderators (language complexity, duration of intervention, and adult interaction), adult interaction was significant, favoring implementation contexts with high levels of adult interaction. Specifically, studies with high adult interaction produced an average positive effect size (g = 0.48), which suggests implications for classroom use. Regarding future research, the authors recommend stronger clarity of theory, attention to learning context, and a more purposeful collection of process data, which can be obtained through greater plurality of methodology.