If you've read Ed's characteristically exuberant Terraria Xbox hands-on, you'll know that it's the first game with a chance of denting Minecraft Xbox 360's previously-unshakeable grip on the hearts and minds of the Xbox Live-playing public. While they aren't immediately similar - Terraria is two-dimensional and more elaborate in its combat - both offer a huge amount of customisation and crafting, to the point where if the provided game isn't sufficiently interesting you can use it to build another one.
You can also, variously, kill unicorns with flamethrower, be killed by a wall of meat, and craft weapons of extreme lethality and complexity. There are a lot of things you need to kill, so this is highly recommended.
As you may have noticed it's a bit hard to explain in abstract, so we aren't going to try. Instead, we have lovingly prepared another video to introduce you to the world and what you can do with it, narrated by our most radio-friendly faces Log and Ed.
Terraria's coming out on Xbox Live this spring, although there's no release date yet.