Video game's approach to storytelling usually comprise of mixing gameplay mechanics (gunplay, health system, enemy AI...) and storytelling elements (cutscenes, dialogue trees, environment details...). There are also special systems designed to work both as gameplay challenge as well as narrative carriers (quick time events, the nemesis system in Shadow of War...)
However, there's also a third approach, where traditional gameplay elements when put into appropriate context within the game gain additional narrative significance (the way Thomas was Alone's basic platforming mechanics are personified via narration, or Undertale's combat system being integral to how the story develops...)
Have you ever noticed if a gameplay element also doubled as a storytelling device in the games you played before? If so, what was it and what did it "tell" you?