We've been discussing a lot how much we want the different worlds (settings) to differ from another. In the end we went with "the worlds should have familiar traits, but each one should at the same time have a very strong personal characteristic to make it unique". This is what we came up with (hope you like it):
For the release we're gonna focus on adding levels with these two setting. However, we've already got plans for the third world, which will be purple and also have different ground tiles.