Mmm, terraforming. <3
Just like Bobik said, not much of it in this vid, but I really like it. Most of my terraforming experience comes from Minecraft, which was childish and not-funny for long-term playing, and from Wurm, which is really archaic and not-so-fun because of "fake 3d world".
The idea of tunnels of different heights make me lust for this game even more. How about showing some terraforming on surface (if it's there yet, of course), raising/lowering ground, flattening etc. Would really appreciate it