Based on apparent time period of Mildenhall and kinda crappy old kid's game's aesthetics of the first few seconds of the Pilot, I like to think that The Circus was made by old man human Kinger in the 90s, and somehow managed to develop VR/AI tech long before the rest of the world gained the technology.
Which is why the terminals and the game are so old and forgotten - this clustershit happened long before it could go viral, and everyone who rediscovers it is subsequently disappeared and forgotten