Bump - as the browser version of the bungie app doesn't work in IE on mobile devices as well as it should (try it, a lot of the menu features just don't work at all), a full companion app for win 8.1 mobile would be a HUGE win. I will give the 3rd party app a try, but have my fingers crossed for an official app. edit: a glance through the reviews at the windows phone app store for this 3rd party app shows just how happy folks were to have a semi-functional Destiny companion app on windows phone. I'm all for supporting our community developers like this person and it looks like a fantastic app, but do hope Bungie considers an official windows app.