1. A method for resolving synchronization conflicts when synchronizing application state data between computing devices, comprising: detecting, at a server, a first set of application state data at a first computing device conflicting with a second set of application state data at a second first computing device, wherein the first set of application state data represents an application state of a computer application running at the first computing device, and the second set of application state data represents another application state of the computer application running at the second computing device; receiving, from the first computing device at the server, a signal indicating that a user has chosen the second set as a preferred set of application state data via an user interface generated by the first computing device, wherein the user interface presents metadata of the first and second sets of application state data including identifications of the first and second computing devices, device types or models of the first and second computing devices, timestamps indicating when the first and second sets of application state data was generated, an identification of the computer application, or progress information indicative of application states represented by the first and second sets of application state data; and transferring, to the first computing device, the second set of application state data to overwrite the first set of application state data at the first computing device.