At present both of my games are what I am considering "City" games. By that I mean that the characters may change, but the core setting will stay the same. The game becomes a story of these people, who live in the city, and their lives. Sometimes that means the focus will stray outside of the city, but it will always come back. The real story then becomes that of the city and how it grows and changes over the time the game is run in it. This presents a variety of challenges, but it also presents some freedoms that you might not expect to be there. Today, I'd like to talk about that.
No Need For A Party
One of the biggest strengths, and challenges, of this kind of game is that it doesn't require a party in the way you would typically think about it. This means that the PCs don't have to get along or work together, in fact they can be enemies or never even interact with each other. This is freeing because it lets the players play who they want without having to worry about group conformity and things like that. It is challenging though because it means it is harder to get people together for big events, and it can make things harder to plan for. On the plus side though, despite having to plan for everyone the things you plan don't have to be as large, and can even be quite personal.
Time Management Is Key
One of the reasons I really like running City games is they let me work on my time management as a GM. Even in the most traditional of games you're going to get times when the party splits up to handle things, and when that happens a large part of how well that session will be received depends on the GM's ability to manage their time. How long can you stay with a player without it being detrimental to other players? How often do you switch off? To whom do you switch off to? What do you do to keep other players engaged while they're not the main foucs? All of these are great skills to have as a GM, and a City game will definitely challenge you on it and help you improve.
Player Played NPCs
This is one of the most awesome strengths the city game can have. Without a party, it is likely that at least two of your PCs will have minimal interaction with each other. because of that, you can assign a regular NPC that interacts with one PC to the other player. This isn't a second PC for them, but when it comes time to RP the player grabs that NPC and runs with it. Almost immediately that NPC begins to act like a real person because they have a players focused attention on them, their needs, and their wants. This gives the added benefit of having a player involved in a scene that their character isn't present for. Which makes everything a lot more awesome.
Downtime and Beginnings
This could just be a personal weakness, but I feel that issues with beginning new plots and handling downtime can be a bit harder with the city game. Particularly because the players can be scattered across the city that getting them involved can make things problematic. Sometimes you just have to embrace the "it's a story, so naturally the PC is at the right place at the right time or wrong place at wrong time" rule and run with it.
Players Have To Jump In
The biggest challenge though is that your players have to be willing to jump in, and if they don't, sometimes you have ot be willing to let them suffer the consequences of not jumping in. If a player is walking down the street and they see a mugging or an armed robbery going on, but do nothing, then maybe the rest of their day is boring while other people get fun stuff. At some point though - and tell the players this - they need to actively opt in to getting involved, because you can dangle plot threads but you can't, and won't, grab them and force them to follow anything. After all, that is kind of how cities work. You get involved...or the city doesn't care.