Zombie Sandcastle - Extreme Castle Makeover

In a version of Zombie Sandcastle that I would describe as anywhere near finished (i.e. not the current version) the player will begin with a building phase, where they get a bit of time to sculpt their sandcastle and place their survivors within it.  However, in the demo I have running there's no building phase, I simply supply the castle pre-built. Which means I get all the castle designing fun. Not wanting to let this little proof of concept go stale I've put a new castle design in the game, which I'm quite taken with. Here it is:

If you've every fancied yourself as a castle designer then sketch one up and send it along to me, it would be great fun to see how other ones play.