Advice: Link your actual app store/list somewhere. On an app-based platform, most people's first question is "what apps can I run on it?"

I think I saw your thing before at an earlier stage because I'm heavily interested in/messing with Sandstorm.io. There's a lot of stuff you can currently run on this that would not work (yet) on Sandstorm, which is cool. Particularly a game server like Minecraft.

My question is what kind of security is employed to ensure apps are frequently updated, apps cannot interfere with other apps, etc.?

You may want to fix how your Terms of Service is presented. On Firefox, it does not word wrap, and scrolls horizontally... pretty much indefinitely inside that box.