A user on WMPoweruser has noticed that the title Crackdown 2: Project Sunburst has gone missing from the Marketplace. The game was made popular when Windows Phone first launched by combining the tower defense genre with actual maps from the Bing maps application. You could pick an actual place on this planet as a playing field and battle mutant freaks in your own backyard.
A number of titles have mysteriously disappeared from the marketplace only for some to reappear later. Hopefully, this title is just receiving an update and will soon be put back in its rightful place.