The game starts off really strong in the beginning but it slows down real fast once you hit the Essence Purifier. Like hitting a brick wall at 50mph kind of slow. This slowness all hinges around the inability to buy any more cisterns, which I don't understand the purpose of, unless the horrible slowness is the purpose, but I hope not. Such a simple restriction turned what could have been an amazing and fun time into one of the worst slogs I've ever played through. I managed to painstakingly, after three days, make elixir, but I did not enjoy my time doing so.
Also, not sure if I fully understand Fast Time because it never happened to me despite my leaving the game for hours at a time.