A Little Bit of Crypto - I have been trying to figure out to "collision resistant" some of these standard hash functions are. It is a tough concept to get my head around. I figure...
You launched your apps using a URI. You cannot use interprocess communication with other apps. That is blocked. The app splash screeen is the fisr thing that is displayed. There are a few view states that an app can be in such as full screen or snapped. The minimum screen resolution for using apps is 1024 x 768.
There is no close command in an app. Your app has to save its state when it is being suspended. The state will later be reloaded. The app settings can be done per user. You need a development account to create apps. To get into the Windows 8 Store, the app needs to pass some tests. Those tests will be conducted with the Windows App Certification Kit. It checks for things like malware and such.