> When you see something in a game like, "Defeat 20 enemies to unlock this achievement", the game is giving you an artificial goal and trying to get your brain to put that on its internal to-do list of tasks it needs to finish.
Not sure about this one. The “defeat 20 enemies” task could be a pointless checkbox, but it could also be an excuse for a fun quest. I could see this pattern not being “dark”, when applied in a user friendly way.
Then again, this is from an article about app badges and I never saw a game use those in a user friendly at all.