My suggestions, which maybe kind of sucky, I don't know, I think that maybe we should have something at the end of the career tree that turns it into a section that you can unlock, and can't come back, like for instance advanced space station technologies vs advanced rocket technologies, or electric technologies that makes it to when you buy one, you can't buy the other tree. It may not be that much of a suggestion and probably not many people would find it worthwhile or anything interesting, but you know, what the heck. But if you think this is a good idea tell me so, in the down theirs I greatly appreciate it!