Who cares about the theme? We will find it out later, what the theme is XD. Elemental temple won, Spaceport was temporary winning...

Cave tiles are cool. I would only remove some stones on corners or even all edges to make it more natural.
Obi, why did You take older version of this "set"? If there wasn't something right you should mention that, if no - try to not miss any tiles.

UR, these angled blocks are not so bad, but we should change its color. Probably, I will do it later.

Sir Ementaler, thank You, it would be easier without You.