This one-group quasi-experimental study aimed to determine the effectiveness of using a gamified course management system with points, badges (and consequently competition) to facilitate the development of English phonology in a foreign language context in Japan. To implement this idea, we focused on the acquisition of English segments /r/ and /l/ in production (as in /r/ock and /l/ock respectively). During the study, participants were asked to engage in gamified pronunciation activities over a period of two weeks, using a popular learning site ("Moodle"). The data collection instruments included pre- and posttests to examine the production development of /r/ and /l/ (using controlled aural elicitation tasks), a written follow-up questionnaire, and user logs to investigate users' perceptions of the pedagogy utilized. The results indicate that participants benefited from the proposed gamified system for L2 pronunciation instruction, as they improved their production of the target English /r/ and /l/ segments. In addition, responses from the interviews and user logs revealed that participants perceived using the site as enjoyable, anxiety-reducing, and pedagogically useful.