In this paper, we investigate the impact of flow (operationalized as heightened challenge and skill), engagement, and immersion on learning in game-based learning environments. The data was gathered through a survey from players (N = 173) of two different learning games (Quantum Spectre: N = 134 and Spumone: N = 40). The results show that engagement in the game has a clear positive effect on learning but immersion in the game does not have a significant effect on learning. Challenge of the game affected learning both directly and via the increased engagement. Skill did not affect learning directly but only via the increased engagement. Perceived challenge was an especially strong predictor of learning outcomes. For the design of educational games, the results imply that the challenge of the game should be able to keep up with the learners growing abilities and learning in order to endorse continued learning in game-based learning environments.