Student response systems (SRS) have been used to provide teachers with immediate feedback on learners' performance to understand their weaknesses and strengths. This exploratory study is aimed at focusing on both distractive and facilitative aspects of using SRS in English as a foreign language (EFL) classes to assess learners' understanding of grammar lessons. Eighty university students majored in English language and literature attended a grammar course accompanied by Kahoot, a free online game-based application as an SRS. Students' perspectives about positive and negative aspects of the application were explored prior and subsequent to its implementation through open-ended surveys and interviews. In addition, their classes were observed for more in-depth information. The results revealed that despite its positive features, most of the students were not willing to take part in this game-based application. They mentioned the Internet connection problems, the high pace of the game, its competitive nature and the lack of detailed explanation after the game as the main reasons for their unwillingness toward using this application in the classroom, which made most of the learners demotivated and distracted. The implications for teachers are also discussed.