This is a fairly neat thing! I am a Sandstorm.io user, so stuff like this is always particularly intriguing. I'm not sure I'm sold on the pseudo-desktop design style, but this looks really clean.

I noticed you have some apps in the marketplace (how'd you get Cut the Rope?), though I see some pretty big gaps, you might want to get a good spreadsheet editor in there by default, for example. The market, as I currently see it, looks like what I expect at the bottom dregs of an off-brand Android phone, despite the notable good examples like Cut the Rope and Telegram.

Do you have a good path for users to import/export their content? This is probably the number one thing I think platforms like this need to focus on. Making it as easy as possible for people to migrate from proprietary sources, and of course, making it easy to leave is just as important.