I don't think video games are the way to spread the message of salvation or the Word of God. Talking to people directly and living by example have and will always be the best evangelism tools. Conforming to the methods and ways of the world is never a good way to reach people . I applaud the Christians using software and IT to teach about the gospel of Christ, but in a video game? This video game also happens to emphasize the wrong things for nonbelievers, and focuses only on (as the Left Behind books do) the end times. End times and prophecies do not make great introductory topics to nonbelievers or new Christians because of the depth of knowledge and spiritual growth that is required. I'm not saying that you can't start learning the Bible at Revelation and Daniel, but those books are heavily predicated on understanding other portions of scripture.
However, if even one person comes to Christ as a result of this, I think it's worth it. I just hope people don't get addicted to this game just for the gaming elements (which I don't think is too likely, anyways).