Realistic Gameplay

There are a lot of games out there who employ realistic game play and photo realism. Some are primarily designed for entertainment, but a lot of them are (or have started out as) what you would call a simulator. Originally designed for use by people ranging from students to industry professionals and the military.

Imagine playing a First-Person Shooter and finding that NOT shooting the bloodthirsty enemies is the expected solution, and merely pointing your gun long enough without firing or firing some warning shots will scare them away with no body count. Since every shooter is designed to let you shoot enemies, why would you think this time would be different? This can also be the result if a Physics Engine or gameplay effect is made to simulate reality (or what people generally accept as "real"note ) without the player knowing, and is suddenly called upon to solve a problem.
Didn't know you could do that? How could you not? It's common sense!
As always, Tropes Are Not Bad. There are a number of games in which part of the game is figuring out the rules , or in which changing the rules is necessary to win. This type of gameplay is simply not very common, which is why it tends to bamboozle and frustrate some players.
Subtrope of Hidden in Plain Sight, sometimes overlaps with Cutting the Knot. Contrast Moon Logic Puzzle, in which the logic which solves the puzzle is so out there that there's no way it was obvious, as well as Misaimed Realism, where an element intended to be realistic only ends up highlighting unrealism.