I had this idea, and liked it so much that I googled it, thinking someone must have made such a mod, but just found this. There is so much potential here for an amazing game/mod! If anyone has played the old never-heard-of-it title M.A.D. Mutually Assured Destruction, you can understand how much fun a game like that would be with KSP level design/customization. For those of you haven't, here's a general concept of MAD: Players start off with territories corresponding roughly to earth political regions Each territory has different population and protective shield You have launch pads to launch satellites into orbit, which give you research possibilities as well as space-based weapons (used to shoot down incoming nukes) You have nukes (ICBMs) that start off really inaccurate + low range, but as you research better technology you can improve the range and accuracy of your rockets, plus increase the payload of the warhead, increase the armor of this missile, making it harder to shoot down, or add things like MIRVs Everything costs money, but you have a steady income based on current surviving population that can be boosted with research Research is done in from your space stations and can be focused on areas such as "improve money/economy", "improve research to get more research", "better sattelites", "better nukes", etc. Ultimately, if the game goes super late, you can unlock doomsday weapons that can be fired from a space station and are virtually unblockable, but required vast amounts of research to unlock, vast amount of money to buy, and vast amounts of power and crew on your space station to operate Now imagine this kind of game, but as a KSP mod where you actually design ICBMs and bombers as well as custom building space stations! If you don't mind decade-old graphics, I would highly recommend checking out MAD, and you will see why this mod needs to be made.
