For those who write mainly video game fics, how do you decide which game elements to put in your fics and which to leave out?

Kinda stupid question but how do y'all decide which elements of the video game or it's universe to put in your fics and which to leave out? Like if your writing a fic about characters from a survival game do y'all try to factor in everything that would be involved in the characters survival realistically or just only the stuff the actual game itself is concerned with? I'm trying to write a RimWorld fic right now and I'm undecided on if I should make the consequences of the usual combat that happens in that game err more on the realistic side, since that would fit the usual tone of the game and how pawns usually meet their end, or should I just do it in the fic the same as it is in the game? And if your writing a fic for a game that has a large modding community, do you feature some stuff from mods in the fic, or only put in stuff that is in vanilla?