It gets better as you watch it, I found myself getting giddy about every 5 minutes of the video.
For those who don't want to watch the video, the name of the game here is evolution (no.. not the actual game, but the concept).
You start out as microscopic, eating things and whatnot in a virtual petri dish type place. After a while you get to lay an egg, and use a creative interface to scult the spawn (ie: Evolve it). There are all sorts of things you can do, not just attachements and whatnot, but actually molding the creature you want, sort of a click and drag type interface. You can do it with all the parts of the body, make it fat, skinny, long tail, short tail, beak, grabberthing, spike, etc.
As you evolve, you eventually go multicellular and much of the same thing takes place, you eat, lay eggs, evolve, etc. Again, with the same huge level of customization. Not merely selecting skins, but able to add appendiges and features wherever you see fit. Not only that, but the game will actually use them in a way that would seem fitting (for instance, an animal you create with a flipper will act like an animal with a flipper, an animal with three legs will walk realistically like something on earth would with three legs).
After that you move onto land, and the same thing takes place.
Now, you get money throughout the game that you can use to purchase certain upgrades in the different body parts, and while you do so you sort of save up money, to buy a bigger brain. That's where things get interesting, since once you get a brain big enough for sentient life, it turns into sort of an real time strategy game, where you're not controlling the individual creature but a small tribe of them, eventually moving onto cities and whatnot.
Then it gets more interesting, since you can eventually have your little species capable of SPACE TRAVEL. Able to go throughout your galaxy, and even out of it into new galaxies.
What makes this all the more interesting is that it's going to be an online game, where the worlds you visit are actually populated by other players creatures, where you can interact, trade, wage war, or even wage peace (hrm

).
Really though, I'm doing a poor job of explaining it, just watch the video.