Learning an additional language without daily exposure to the language may hinder the learners’ reasonable level of improvement. Thanks to the growth of digital technology, exposure to learning materials in digitally accessible forms is possible, especially in English language and for English language learning. Digital games, evidently in a wide range of literature, can be one of the effective language-learning supplement to enhance the target language acquisition, support constructivist learning, complement the deep level of cognition, encourage a willingness to communicate, increase social interaction, and at the same time, promote learner autonomy. Nevertheless, its impact on the improvement of language proficiency resulted from informal learning with an educational game remains obscure. This study thus utilised a language-learning digital game (LLDG) as an edutainment supplement for the out-of-class practice of English as a foreign language (EFL) students at a tertiary level for eight weeks in order to answer this question. The comparison of the listening test scores between the control group and the experimental group obtained in the pre-intervention and post-intervention has affirmed its positive impact on learners’ proficiency. This is despite that the investigation of the learners’ experiences, through questionnaires, shows that the game design has an influence over the learners’ behaviour in the learning. The results suggest that a practical design of an LLDG that values learners’ needs for self-esteem development along with the language proficiency and simplifies for ease of use without a digital literacy required could contribute to successful pedagogical development for both formal and informal settings.