To quote the Game Ideas thread: “(I’d like to make) a heist game, where you have the task of putting together a team, and planning and executing a heist. You would have the choice of several different NPCs for your team, and, while the game would fairly short, it would be extremely replayable, because you could build new teams and have a whole new dynamic every time.”
Basically, all NPCs react differently to each other. Maybe A is the best safecracker in the business, but if you piss him off, he won’t agree to be part of your team. B isn’t as good, but he’s willing to work for you … except, he continuously pisses off C. So you don’t choose C, you choose D for your team, and D and B get along fine. But D might prefer an explosive entrance to your sneaky plan. So, in essence, the characters react to each other; you have new conflicts or a new dynamic every time. One lineup might allow you to pull off the heist without a hitch, but then you have to contend with a double cross. Another lineup might be more reliable but your team will squabble all the time. Things like that. Experimenting with new lineups would add a ton of replayability.
It’s a very complex idea, and I’m not sure how complicated it would be to code such a game.