Half Life 2: Despite Zombie Chopper only having 6.9% of steam players actually get it, including myself, it’s arguably the more famous of the Half Life 2 achievements.
Please, Don’t Touch Anything is a puzzle game where the player is presented with an empty room and a button, and pressing it unlocks more knobs and switches and levers that they have to figure out how to press to unlock endings. When it comes to the achievement for simply pressing the button, only 96.6% of all players have gotten it. That means a shocking 3.4% looked at the button and decided to just not press it and then didn’t continue playing the game.
The Talos Principle: About 20% of players have gotten the achievement for getting the “canon” ending of the game, but only 6.1% of players got the achievement for going up to where the canon ending takes place, changing their mind, and walking back down.
Myst (2021): In the 2021 remake a shocking 32% of players made it through Selenitic, but only 4.6% got the “Never Lost” achievement. This is a bit of a big leap in logic, I’ll admit, but I’m willing to bet that means only 4% of players actually know how to solve the mazerunner puzzle. It’s a puzzle you must solve to complete Selenitic. Without going into it too much, you control a train going through a maze of rails and at each junction you can spin to go to a set of different rails. Each cardinal direction corresponds to a series of 4 sounds you were supposed to have memorized from the previous age (level), the Mechanical age. If 2 sounds happen, then you have to go in the direction between those sounds. If you play the game in the non-randomized state then you can just look up a walkthrough of this puzzle, which is what most people did in the 90s and what most people still do because guaranteeing good sound quality for everyone is still difficult. Most new players might even play with the sound off just because they don’t know about this.