I’ve played through the game about 11 times already. Started a 12th game. No “gameplay hints” (++±–) were showing up. Thought it would be just a little glitch. So I started yet another new file, same thing. Then I turned off the game, started it again, and upon beginning a new file, the achievement “Support An Indie Developer” appeared as if it was my first time playing. The old save files are still there. I then loaded into one, and my progress in it is intact except for the “hints” are gone and all the achievements as well.
There were no error messages. I use no mods at all.