We explored whether problem-solving interactivity within an instructional game fosters learning for children aged 8-10 years. Participants (N=139) studied a biological topic either through a game-based learning environment (in which they solved assigned problems by interacting with a plant model) or from a standard learning environment (in which they observed how the problems were solved in an animation) (i.e., between-subject design). The treatments were equal with regard to learning content and guidance. No between-group differences in learning outcomes were detected (comprehension: d=0.16; transfer: d=-0.01). Self-rating of enjoyment tended to be higher in the game group (d=0.32), and when the children could choose between the treatments in a free-choice period, they strongly preferred the interactive game (87.5%). The results suggest that both the interactive and the non-interactive treatments are useful, but their applicability may differ depending on the learning context (e.g., school vs. home).