In recent years, the integration of digital technologies into language learning has gained significant attention, particularly in the context of English as a Foreign Language (EFL) education. However, there remains a gap in understanding the broader affective and cognitive benefits of serious game-based learning (SGBL) in this field. The present study addressed this gap by examining the impact of SGBL on EFL learners' happiness, motivation, self-compassion (SC), and vocabulary development. A quasi-experimental design was employed with two groups comprising a total of 425 intermediate-level participants (both male and female). The participants were selected through stratified random sampling technique and divided into an experimental group (EG) and a control group (CG). The EG engaged in SGBL, while the CG received traditional instruction. Over a period of 12 weeks, pretest and posttest measured the participants' levels of happiness, motivation, SC, and vocabulary acquisition. Results indicated that the EG significantly outperformed the CG in all measured domains, suggesting that SGBL is an effective approach for enhancing both affective and linguistic outcomes in EFL contexts. The findings contribute to the growing body of research on the integration of digital games in EFL education and highlight their potential for fostering holistic learner development.