While some may grumble it’s not online co-op, Update #2 for Terraria-like world-builder Dinora (original review here) does bring friends into the mix via split-screen play. You and up to three(!) of your pals can now brave the dangers / experience the highs of molding a world in your image… together. Perhaps even better news, you now have access to four save slots, meaning you’re no longer confined to just one character or vision of said molded world.
Weather in Dinora takes a turn for the random, as well, with new dynamic rain / snow systems to account for. Also addressed in this update are some performance quirks and bug fixes. It introduces some new ones, too, apparently, though a game this massive is going to constantly evolve (and improve) with each new patch. If you’ve been sitting on the proverbial fence until now, it’s time to hop off. The game is good fun.
theXBLIG 
Great game and they continue to upgrade and take feedback from the players. This game is worth even more than they are asking.
If you haven’t gone adventuring in Dinora yet, and would like to, first person to reply to this comment wins a copy of the game, courtesy of the developer.
Orah!
Lets dig up a legend.
Congrats! Code is yours. I shall send it in a few.