The update is scheduled to arrive mid-May and will include a new playable map that is "roughly the size of the original map," new achievements, new goats and more alongside the split-screen multiplayer. Offering online multiplayer is not possible at this stage, according to the announcement, due to physics synchronization difficulties.
"A lot of you have been asking for DLCs for Goat Simulator. However, since we have Steam Workshop support, we'd feel bad charging for DLC when you can just download stuff for free at the workshop," wrote game designer Armin Ibrisagic. "We still want to make new content though, so we found a compromise: we're going to add a completely free content update with patch 1.1, coming in the middle of May! As we've announced before, online multiplayer doesn't quite work with Goat Simulator since we can't synchronize the physics we're using across different computers, but local co-op with splitscreen should work!"