Kingdom is something I've been working on for a few weeks (off and on). I liked the idea of making a game where you can build castles, fight dragons / monsters, go on quests and basically build up your own 'kingdom'.
DEMO V1.0.1 - 19th June 2013
A number of features I'd like to add are:
Castle building - I'd like this to be quite flexible and organic. I want the player to be able to build their castle how they want to, a turret here, a tower their etc. I want it to feel really natural and fun. Also castles need to be destroyable...
NPC's - These will come to your Kingdom as you build and make it more attractive. The safer you make your Kingdom the more people will flock to it. The more NPC's you have the more resources will be gathered and more items will become available. NPC's will occasionally be campaign characters.
Campaign Characters - These characters will join your "King" for quests etc and can be selected / deselected from your team. Wizards, Knights, Archers etc.
Creatures - Horses, Tigers, Dragons and many more creatures will roam the land. Some can be ridden or used in battle if tamed.
Quests - Some will be found in the land as you wander around, some will come and find you.
I'm not sure how far I'll get with this one but I'm very pleased with what I have so far. My trees and grass all blow in the wind (I'm very pleased with the general style of the environment) and soon I'll be adding Castle Building to the game which is a
major feature. It might get complicated...
Edit: The sky is actually a 3D skybox made using my "EnviroScope" tool (Oilified in GIMP). It was a really simple way of making the sky. I just rotate the camera a little to give the parallax effect

this.mess = abs(sin(times#))