Well, I mentioned that one time that the tech tree got cut off, I could not get communism, so in the future era I was cut off from researching some of the techs and I could not advance. I have seen this happen to the computer before. It was hugely ahead of me in tech, then it stopped for some reason, and I was able to get caught up, it never progressed, that is why.
As for buildings, some of them you build and they disapear. Such as cement mills, ammunition factories, steel mill, distileries. You can only build 4 of them. If you build the 5th one, one disapears somewhere, so you can never have 5. Octoberfest is an impossible wonder to build as well.
The tech tree is really good, I am sure you could add a few more things, though it is without a doubt the best tech tree of any civ mod. I can no longer play regular games, this mod puts regular games to shame. Just iron out a few of those things, would make it great.
One idea for a tech, a future tech might be space paratroopers. An advanced unit that can land anywhere on the world, because they are landing from space. Or how about a fusion bomb, something that explodes on even more squares. Another wonder you could have would be WAY in the future. It could do something with a bonus of colonizing other planets. Once you build it, it would provide reinforcements every turn, simulating that your other planet is sending troops back to earth to help.