The Test-of-English-for-International-Communication (TOEIC) is an important proficiency test for achieving the benchmark of future employment for English language learners worldwide. However, game-based apps for acquiring TOEIC vocabulary have remained scarce. Therefore, an empirical study was conducted to examine the effects of the self-developed the smartphone app "Saving Alice" for optimizing the acquisition of TOEIC vocabulary and spelling among EFL learners. Multiple sources of data were collected to investigate how "Saving Alice" affected vocabulary acquisition, including a demographic survey, pre- and post-tests on TOEIC vocabulary, and semi-structured interviews. Both the quantitative and qualitative findings showed that "Saving Alice" significantly enhanced the student learning outcomes, and that frequency of using game-based mobile apps (GBMAs) correlated with learning outcomes.