Background: Game-based learning can frame problem-solving as a sense-making experience with domain-specific tasks for school students. However, multiple challenges arise when trying to support learners in such a complex, problem-oriented learning environment. Objectives and Methods: With an architecture-themed mathematics learning game, we conducted two mixed-method studies to explore the impact and design of game-based mathematical experience on the math problem-solving performance of middle school students. Results and Conclusions: The study findings suggested a positive impact of game-based math experience on math problem-solving for middle school students. Problematization-oriented game-based math tasks with structuring features enhanced students' reasoning with problems and channelled it to doing mathematics. Takeaways: The current research findings support the initiative to frame learning as a sense-making experience with domain-specific tasks and inform the design of game-based mathematical experience and learning support.