Here are some of the tech tree prerequisite cuts I am considering. None of these are truly redundant prerequisites, but I don't think any of these really contribute to the overall goal of the tech tree of providing a plausible path of technological advancement. Calendar -> Astronomy: This is a holdover from BTS. In BTS, Astronomy's prerequisites are Calendar + Optics, and Astronomy is Calendar's only exit point. In AND, Astronomy also requires Algebra and Compass, and Calendar also exits to Crop Rotation and Clockworks. Astronomy does not need to have four prerequisites, and Calendar is two eras back. The Calendar to Astronomy jump is the fifth-longest jump on the tech tree. This is one connection that can be cut with only leaving a very small potential hole that I don't think offers an exploit. Calendar probably needs a Classical Era exit point, but I can't think of one right now. Civil Service -> Invention: Civil Service is the fourth prerequisite on Invention, besides Alchemy, Engineering and Guilds. Civil Service is the only prerequisite that is in the Medieval Era's first column rather than later. Clockworks -> Scientific Method: Another fourth-prerequisite tech. Here we have Scientific Method requiring Astronomy, Anatomy, and Printing Press, all of which are Renaissance techs themselves, and then Clockworks as a Medieval Era tech. Clockworks also exits to Matchlock and Navigation, both important techs themselves. Anatomy is actually the tech that pins Scientific Method to its current place on the tree. I do like not having Scientific Method too early in the Renaissance. Semiconductors -> Fiber Optics: I noticed that Robotics and Fiber Optics have very similar prerequisites. Robotics requires Laser and Semiconductors, while Fiber Optics requires Laser and Semiconductors and Synthetic Fibers. I don't like that much overlap, so I think cutting Semiconductors from FO is fine. Semiconductors also leads to Composites and Microprocessor so losing one exit point out of 4 doesn't hurt. Advanced Computers -> Orbital Flight: Orbital Flight has 3 other required techs (Biomimetics, Skyroads, and Space Stations) and either Biomimetics or Skyroads will pin it in place. Advanced Computers leads to EIGHT other techs, more than any other AND tech. Losing one will totally not bother it at all.