People like to make things complicated that don't have to be. It happens in life and it happens in the world of videogames. Look at some of the progress trees games like those in the Final Fantasy series sport. They may great, but they are also hugely detailed and if you try to picture them in their entirety your brain may explode.
Sometimes that old acronym, KISS, is exactly right and you should just keep it simple, stupid. In 2007 Valve released the first Portal game and the gameplay concept really couldn't have been more simple – each room is a puzzle where you have to get from the beginning to the end. You have no weapons, just an Aperture Science Handheld Portal Device, or, if you will, a "portal gun." You can fire your portal gun and make holes in walls that will transfer you from one part of the room to another (as you progress you can make two holes to decide where you're going from and too whereas initially one of those locations is predetermined with an already existing hole and you just get to make a second). Other things like lasers and blocks can also go through the portal hole, and your job is to figure out how to best utilize your portal gun to traverse each room.
Portal really is a very simple concept – get from one place to another using mainly your wits. Each level may take you anywhere from 30 seconds to a full hour to complete depending on when exactly you have that moment of clarity which allows you to see the puzzle from a new perspective and thereby find the answer.
On top of that concept, Valve placed something of a minimalist, but nonetheless fascinating (I refer to it this way because you have very little agency in it), tale about a computer, Genetic Lifeform and Disk Operating System (GLaDOS), going somewhat haywire. You uncover what is taking place with GLaDOS as you go through the game and, at the end of the title, you beat her (she speaks with a woman's voice, so we're going to call it a "her").