A World of Keflings: It Came From Outer Space is more fun with the Keflings. The game retains all of the charm and gameplay found in previous games, only adding an intergalactic spin as a group of Kefling-like aliens crash land in the Keflings' homeworld and search for a way to repair their ship.
Gameplay remains largely unchanged from past games. You play as a giant (represented as your XBL Avatar) who helps the little Keflings build their village. Each mission involves setting up tiny assembly lines of Keflings harvesting resources and bringing them to their corresponding buildings. From there, you can build smaller parts needed to construct larger buildings.
Structures are slightly different in It Came From Outer Space. Rather than including a bunch of specialized structures, each structure is split into a couple of specialized types. For instance, the normal refinery (a giant, caged space lobster) normally produces bricks when fed sand. After feeding it a space carrot, however, it can produce radioactive ore, which is needed for certain structures. The new setup doesn't alleviate the need for multiple buildings, though it does offer some flexibility in your build strategy.
It Came From Outer Space also makes it easier to keep track of which workers are doing what. Once assigned to a task, the alien's head takes a different shape that is easy to quickly pick out from the crowded space.