I never understood that requirement. I would like to have it use one of the more recent buildings (e.g. Automated Mine) but that would be a problem because they are still in the core. I'll think of something. Haven't put too much effort into the balance. I will take a closer look. I'll do that for the Lunar Worker. Good catch. I'll give it an upgrade. There is the Venus Hydrogen Generator, which splits hydrogen from the atmosphere. Maybe a separate refinery could separate ordinary hydrogen from deuterium. But yes, there is a need for a few more early Venus buildings. Will shorten it. Apparently. Furthermore, in some cases the natural rush cost goes so high that it overflows and becomes 1 gold. Not sure what to do about that. The Asteroid Mining Complex comes later in the tree (Lunar Trade vs. Lunar Manufacturing), so don't forget to take that into account. Since I just did a major reduction in extraterrestrial wonder costs, I want to hold off a bit before revising those formulas again. That's a strange one. The intention must have been to not allow Body Exchange Clinic in every city. I will take a look at it.