Fortnite is a new sandbox style game for the PC, but the big deal here is that it showcases the Unreal Engine 4. Since many, many games are based on Unreal Engine 3, yes, that one — that one, too — it will be worth watching to see how this next version of the grindy gears behind the game works out. As for Fortnite itself, it looks like Super Treehouse Simulator 2000, where you build up a ramshackle fortress against monsters who seek to destroy the fruits of your labor board by board. Check out this article about Fortnite and the Unreal Engine 4. It even includes a before and after comparison between version 3 and 4. GameInformer has the story.