<p>Promoting pro-environmental behavior has become increasingly urgent in the context of accelerating ecological degradation. Drawing on spillover theory, this study investigates whether and how engagement in environmental serious games promotes real-world-oriented pro-environmental intentions and willingness through cognitive and affective mechanisms. Across four controlled experiments, we show that environmental serious games can foster such responses beyond the virtual context. This behavioral transfer is consistent with two parallel, empirically distinct pathways modeled as simultaneous mediators, namely environmental self-efficacy as the cognitive pathway and nature empathy as the affective pathway. Furthermore, the spillover effect is differentially moderated by the valence of an induced state of awe and by an induced state of connectedness to nature. Specifically, awe of beautiful nature amplifies the transfer, whereas awe of threatening nature attenuates it, and a heightened state of connectedness to nature strengthens it. Because the outcomes were behavioral intentions and commitment-based measures rather than directly observed behavior, the findings are interpreted as evidence on pro-environmental intentions and willingness. Together, these findings advance a cognitive-affective dual-pathway spillover model that explains how digitally mediated environmental experiences shape these responses. This study extends spillover theory to virtual-to-real behavioral contexts and offers actionable implications for environmental serious game design and digital environmental education.</p>