Dev here. I'm truly sorry about this. The app indeed has been crashing for many users for the past few days. I am not trying to shift responsibility away from me, but as far as I can tell, these are issues related with Windows Phone 8.1 and not with the app. Of course it is still my responsibility to fix it, but it has taken a lot of trial and error; I also haven't been able to really work on the app for the past week.
There are at least 2 (OS-related) bugs involved here. The first one was addressed with update 3.0.3. The second one that I am at this point aware of, hasn't been addressed yet with an update. However the removing secondary tiles fix described above is spot on as a temporary workaround. However, since the workaround seems that it doesn't work for a few users, it seems that there is probably also a third bug somewhere there (don't know yet if this is OS-related or not).
For anyone that has tried removing all secondary tiles, and is still unable to launch the app, please send me an email as I could really use your feedback for this.