In-game learning supports aim to help students solve game levels (i.e., game-related supports), and connect to underlying content (i.e., content-related and hybrid supports). Students with different levels of prior knowledge may have different needs for in-game supports. In this study, we designed a 2D physics game with game-related, content-related, and hybrid supports to explore the relationships among students' prior knowledge, their access of learning supports, learning outcomes, and game performance. Our sample included 199 ninth- to eleventh-grade students from a K-12 school in the southeastern US. Our findings indicated that students, regardless of their degree of prior knowledge, tended to access supports that directly addressed the solution of game levels (game-related supports) rather than those which presented content (content-related and hybrid supports). We found that the more frequently students accessed the "hybrid supports," the greater their knowledge acquisition, and the more game levels they solved. We found no significant relations between the access of game-related and content-related supports and students' learning and game performance. Moreover, students with high prior knowledge tended to use hybrid supports more frequently than those with low prior knowledge. Implications of our findings and suggestions regarding future research are discussed.