This was an awesome idea, like a portable version of Minecraft. Building was a lot of fun, though it would be great if you could rotate the world yourself, and view it from any angle you like. When you can only see it from diagonal angles it gets easy to misalign tiles between layers. It'd also be awesome with the option to save levels as shared creations, through the NG API so they're all stored online and viewable. Apart from that this was good fun. Plenty of potential to expand with new features/grid sizes/etc. Nice work!
-cd-