The secrecy must be unrewarding, but it’s the best defense against lawsuit-happy IP holders. When word of mouth begins to spread, you better be ready to release and run because it’s only a matter of time before Nintendo’s lawyers start gunning for you.
Guild Wars 2 has been my theme park MMORPG of choice on and off for the last 12 years, with >2500h. I have also spent ~1000h on Elite Dangerous.