Purpose: This paper aims to examine whether the instructional message used to introduce game-based learning (GBL), prior knowledge, flow and prior gaming experience have an impact on secondary students' learning outcomes, perceived game utility and motivation to use the game. Design/methodology/approach: Fifty-four 9th grades students enrolled in this quasi-experimental study. Both groups played the same game. The experimental group was told that they would be playing a game, whereas the control group was told that they would be doing an exercise. The game was designed to promote knowledge recall about familiar mathematical concepts. Prior knowledge was assessed. An immediate and a two-days delayed post-evaluated learning outcomes. Flow, prior gaming experience, perceived game utility and motivation to use the game were assessed with questionnaires after playing. Findings: Introducing the GBL activity as a game increased immediate learning outcomes for low knowledgeable students, but these benefits did not extend to longer term. Indeed, when the GBL activity was presented as an exercise, low higher knowledgeable students obtained poorer longer-term learning outcomes than more knowledgeable ones, whereas no difference appeared when the GBL was introduced as an exercise. Prior gaming experience and the type of instructional message used to introduce a GBL activity positively influenced perceived game utility and motivation to use the game. Originality/value: This study is the first to highlight that the way a GBL activity is framed affects differently low and higher knowledgeable students' learning outcomes and influences perceived game utility and motivation to use the game.