The presented research discusses students’ perceptions, attitudes and expectations of a game-mediated vocabulary app. Throughout the development of the mobile app, continuous focus group interviews with students were held. The collected data were coded and analysed to identify common features or points mentioned by the students. The results showed that students highly value features like the story plot, graphic, vocabulary list and types of definitions for the design of vocabulary learning APPs. Based on these findings, the APP was further improved by adding synonyms, sentence contexts and extended definitions of the words. Our followed-up interviews indicated that students rated the improved version of the APP higher than the preliminary one. Such findings are consistent with Zou’s (2016, 2017) arguments that the availability of various aspects of word knowledge are conducive to effective word learning as it promotes greater degree of elaboration on the target vocabulary. Copyright © 2018 individual authors.