The game can be purchased for $14.99 on Steam early access right now, but don't expect a full game if you decide to spend the money. Developers at TT Games write on the official Steam page for the game that they decided to go early access with Lego Worlds because they want to have gamer experience help drive development.
The current plan, they write, is to keep the game in early access through the end of the year. Once they've added what they want, they hope to release the full game sometime early next year.
Among the things planned to be added to the final release are underground cave systems, better AI, more weapons, vehicles, characters and creatures. And, perhaps most importantly, multiplayer.
Until then, here's an early look at what might become the next big sandbox game.