I like how he blindly assumes that there was a "system time", or that there was a way to asynchronously poll for keyboard input. At least on the Apple II I grew up with, timekeeping required third-party hardware, and the only way to get user-input without writing assembly was INPUT, which paused the program until the user typed something and hit Return.
User inputted seeds were in a lot of classic text based, randomly generated games - by sharing the seed with friends, you could play through exactly the same game and see who did it better. Multiplayer!