The use of games in education has become increasingly popular. However, having the idea that games are merely for entertainment and full of violent/indecent content, many parents and teachers in Taiwan often consider game playing to be useless and even harmful to students. Thus, games are not welcomed in various educational settings. If Taiwanese teachers hold a more positive attitude toward video games, it is more likely for them to incorporate game-based language learning (GBLL). To change teachers' stereotypical views toward the value of video games for language learning, it is essential to first allow teachers to explore the potentials of GBLL. In this study, we first introduced GBLL to 20 pre-service teachers in one computer-assisted language learning (CALL) course, and asked them to play a commercial video game Back to the Future for 12 weeks. The video game is based on the story of the famous movie Back to the Future. In the game, the player controls the leading character, Marty, to explore the 3D environments using either the keyboard, mouse or game controller to move around. The pre-service teachers were allowed to play the video game for one hour each week. After 12 weeks, all the teachers were asked to write a formal evaluation report discussing how they feel about using adventure video games in English learning. After carefully analyzing the reports written by these teachers, we found that these pre-service teachers showed very positive attitudes toward the video game and also identified several reasons why games could be an attractive and motivating tool for second language learning. As for language learning, teachers observed that video games can be very useful for vocabulary, listening, and reading development, and can even enhance students' logical thinking and reasoning abilities. They, however, pointed out that the game is limited in developing speaking and writing skills. Teachers also expressed their concerns over the following issues: 1) Game design and content for ESL learners, 2) the financial support needed for implementing GBLL, 3) the teaching and learning strategies required for implementing GBLL, and 4) the learning gains achieved through GBLL. The research findings of this study provide game researchers several possible research directions and also offer valuable suggestions for school teachers who intend to incorporate video games in second language teaching and learning.