So first problem, the music didn't play. I waited about a minute after the first story bit seemed to end with no sound and wondered if i'd made a mistake. So i aborted the mission and restarted, double-checking the settings. Playlist = Exercise, GPS checked, Zombie chase checked. Still no music.
Then after going awhile and checking i found that nothing was showing up for the distance traveled, and no zombies ever seemed to chase me.
Curiously right towards the end it suddenly registered 1.67 miles. Also "coincidentally" that was at least part of the route that Cardiotrainer missed. Perhaps only one app can query the GPS at a time? That doesn't really make any sense, but next time i'll try it without running Cardiotrainer at the same time (and then be very sad if i end up with absolutely no record.) No idea about the music thing though.