It is very common for game designers to be asked about their work. It is normally supposed that they are responsible for drawing, animating or other artistic tasks. When they reply that it is not their work, the questions come. Some designers argue that they are the only ones who truly create the games, a bit pretentious because they forget the rest of the developers ... Others say they simply write the necessary documentation or start talking about the mechanics of the game, GDD, and other specific concepts.
The most tricky ones begin to make beautiful comparisons, as with architects or film directors. However, many recognize that they do not know what their work is about. But they lie.
What videogame designers really do is that, to lie. Tell stories, manipulate the player, deceive him and make him believe the lies. In the end, everything is the same but it is better to call this illusion. The key here is that the player wants this lies, he wants this illusion of the game.
It starts in the description or trailer, the first information of the game "Prepare to be enchanted by a world where the choices you make and the paths you choose shape your destiny" or "Take control of the civilization from the beginning of the time". This has some truth, as good lies, but technically is an illusion of choices or control. It is an illusion of game and it works with the player's imagination (he wants to believe) and game conventionalities, that the player accepts.
What is a game conventionality? Well, in short, it is every part of the game that differs from reality. Many of them are generally accepted. For example, the life bar that drains with damage and restores with time or medkits. Real medicine works differently. Game conventionality is a big theme and I will write more about it but if you want to understand how many game conventionalities we have, just sit your parents or another person, who never plays, to play videogames. You will see how lost they are because they don't understand these conventionalities.
So the game is an illusion that works with the player's imagination and conventionalities. But why does the player want to believe? Simply, for fun, to experiment something different from his real life. To feel the control.
Here is another big point: to accept this illusion the player needs to know that he has control in the game. That is not a total control, just the feeling of the power. We all need to know that we have the power to control our decisions and actions. The real-life is difficult in this but the videogames normally give the player some control for this feeling of power. The player can: save-load, retry the level, create a new character... and there are more instruments but the game developer must understand what grade of control he gives to his player in the game illusion.
However, the player can stop believing in the game illusion. Usually it is something momentary and disappears, but sometimes it is a constant feeling. Why does it happen? Well, normally it is because of the dissonance. The player just sees the lies. There can be many things from the bugs, that just break some parts of the game, to the ludonarrative dissonance, where narrative crashes with the gameplay. Some conventionalities can trigger dissonance too, especially when the developer does not explain it. The old tutorials, where the developers explain to the players directly how to play the game, breaking the fourth wall, are dissonance too. But it happens at the start and normally the player feels he must suffer it to get fun after.
In conclusion, what game designers do? We try to tell interesting lies and create fun illusions to our players, that want to experience this. We give them some feeling of power that they do not have in real life. We try not to get caught with our lies. And we believe in our illusions too, it is a base for the good lie - to believe in it yourself.