I don't have much to show quite yet, but we started off working on icons for the game.
It's basically tower defense where players go head to head. One player defends a lone tree from their opponent utilizing a host of weaponry, shown in the first three rows, such as cannons, anti-air missiles, and so forth. The weapons can be upgraded using a branching tree system.
For instance, this represents the Mortar Tree. From the first level Mortar, you could upgrade to the Quake and then Fissure weapon; or you could go the bottom route and upgrade to the Frost, and then Hailstorm weapon. They've all got their own strengths and particularities so there's definitely a lot of room for strategy depending on the situation.
The opposite player's job is to use an army of Creeps (shown in the bottom row of the grid) to set fire to the defender's lone tree. There are a few different types so far, each with their own abiliites, and we're looking to work on more types in the future.
That should give you an overview of the game, but take a look here for more insight. http://creativegametheory.com/ It explains in a bit more detail and it's updated with general progress on the development. It's a really fun concept for tower defense, I feel pretty fortunate to be able to work on this and hopefully I'll have more to show soon.