So far, Terraria has been having a pretty good week. It became the first title in a long time to outsell Mindcraft on Xbox Live Arcade, and has had a fairly good launch otherwise. Developer Re-Logic talked about Terraria getting some new features for the PC, and recently some screenshots have been posted on the official Terraria forums indicating the same.
The descriptions are quite simple: Floating islands and jungle waterfalls. So players who want to further customize their environments and bases now have even more choices to do so. Hopefully we get a chance to either create a giant fortress of floating death or the equivalent of Atlantis.
Terraria is an open world game just like Minecraft. It is randomly generated and one can build anything out of nothing, while defending against random monsters and exploring even more random areas. It diverges from Mindcraft by taking place from a 2D-side scrolling perspective.