Not at all! They have different mechanics, yes, but different stories and scripts too. Mechanics to me are jumping, attacking techniques, etc… i.e. movement and collisions. Inside a genre, it’s common to have some similarity in mechanics. As a player, when I play a FPS, what I think mostly stands out is the story and the context. That’s important at least equally as if I jump in a way or another.
My mechanics are mainly the common in survival horrors with some puzzle solving. But I think the originality resides in the story. If you tell me that all I need is a completely original and strong mechanics and all the rest is a further detail, I’ll accept it, and recognize maybe I’m biased towards storytelling and game art more than everything else 