There's a thread on theRPGsite
that might be good reading for you. I haven't looked through the whole thing, but it does mention CthulhuBusters and combines rules with an "actual play" recount of his campaign.
For those interested in the rules but not interested in wandering through the thread, I did a copy-paste of some key rules posts so you can read them below.Rules
The game is more or less using the 5th edition rules of CoC (since that's the book I own). There are some changes, though, and I typed up my own "Player's Guide" set of rules for my players to use (sorry, due to copyright issues I can't distribute). Some of the changes were to make the game more Gangbustersy, others just to clean things up a bit.
Stats are all the same as standard CoC. I did change up the occupations to include Gangbuster-relevent occupations (mostly taken from the CoC Investigator's Companion) and set investigator income based on the social class for the occupation selected.
One thing I did add a whole page on is ethnicity - the Gangbusters world is very ethnicity focused (ethnic gangs, anti-immigration fervor, etc.). Picking a character's ethnicity is a big deal in my campaign.
I completely revamped the skills list (sorry, CoC/BRP purists). I use the same default percentages model and skill resolution rules, but the skills themselves have been changed. They come very close to resembling most of the skills from Trail of Cthulhu (Firearms is a single skill, various scientific skills are split out, no own language skill, dodging just uses a general athletics skill, etc.) I also used the Trail of Cthulhu style of explaining what each skill could be used for. Although I do not prefer ToC overall, I feel they did a lot better with their skill writeups than regular CoC does (they also have more inclusion of police and criminal skills, which are essential for the Gangbusters aspect of my campaign).
Combat rules has some changes added. I included some rules from Deluxe BRP (aiming, concentration, some attack modifiers) as well as some others adapted from GURPS (diving for cover, changing posture), Top Secret/SI (using the tens digit for hit location - if needed, reloading rules), and Gangbusters (a lot of different modifiers to hit with firearms).
Firearms probably had the biggest overhaul in rules. I replaced CoC/BRP style burst rules with ones that approximate Palladium's firearms rules. I also added recoil rules for firing more than one shot per round (with recoil based on the weapon; higher calibers having more recoil).
The vehicle rules were changed quite a bit as well. I started with the Deluxe BRP "car chase" rules, but expanded them out quite a bit based on the Gangbusters rules for handling vehicle hits, crashes, and special manuevers.
As an appendix, I added a rather large weapons list (again, part of the campaign flavor) with pictures of each weapon type and who was likely to use it. I standardized the weapons stats a bit so that weapons of the same type always had the same number of shots per round, similar calibers of the same weapon type had similar recoil and damage values, etc.Theme
I'll start by saying that my take is subtly including CoC elements into a Gangbusters-style world. What I'm not going for is something like the "Cast a Deadly Spell" movie or the "Bloodshadows" RPG where you are trying to do a noir game in a fantasy setting (the "historical Shadowrun" take, if you will); not that there's anything wrong with that approach, it's just not my cup of tea.
Instead, I'm basically taking your standard noir and adding in an extra element of the fantastic. If you look at the stories of Dashiell Hammet for example (my personal favorite noir writer), he has multiple stories where secret cults are involved. I'm basically saying, hey, instead of freaky 20's sex cults (the usual staple of noir stories), why couldn't they be cults of Cthulhu entities?Setting
The setting I'll be using for the game is Lakefront City, the pseudo-Chicago setting that TSR created for Gangbusters. I have the 3rd edition which includes the "Trouble Brewing" module in the back that sets up a whole sandbox of city mayhem so I'll be starting off using a fair amount of that.
I picked the year of 1924 for my starting date; part of my plots involve an upcoming election and that year fell in nicely.
I created a whole city guide for my players (again, can't share that since I am co-opting some copyrighted material).
I started by discussing the local industry information. This was an area that TSR more or less ignored, as they were focused solely on the cops and robbers aspects. But the rise of big business is a pretty big theme of the decade, and the conflict between businesses, unions, and criminals fuels all of the politics of the time.
Next, there's a big section on crime. I use the Tolino and O'Conner gangs from the TSR material (stand-ins for Capone and Dean O'Banion), but added some more as well - such as the Magenta Gang (my stand-in for the Purple Gang), the Jefferson Gang (a black syndicate based on Bumpy Johnson's Harlem gang), and even a gang based on Rocco Dillon from Naked Gun 33 1/3 (what can I say, I like Fred Ward). I also added in the very real On Leong and Hop Sing tongs for the Chinatown gangs (with one of them led by Chang Li Ching, my favorite villain of Hammet's).
Some of the characters are actually NPCs I've used before in different campaigns. I added the O'Banion Brothers, John T. and James, as henchmen for O'Conner (they are based on the characters of the same names from "Legends of the Fall" and have been included in roughly half of the games I've ran since the 90's as my generic, murderous Irish gangsters - they've showed up in D&D, Earthdawn, Rifts...) The Jefferson gang is led by "Whisper", a guy with a previously slashed throat that can barely speak that I've previously used in a Cthulhu campaign - last time he was a Cajun gangster in New Orleans (I know I'm stealing him from some form of fiction, but can't remember what originally inspired me).
One of the biggest differences I've made is a change in mood from the TSR setting. TSR was going for a more family-friendly, lighthearted take where bootlegging and gambling were the main crimes. My setting adds back in the other lucerative criminal industries of prostitution and drugs (particularly with the Chinese gangs who are the major source of the drug of the decade, opium / heroin). The criminal elements in my game are not romanticized, but given the hard edge of noir where they are bad people doing bad things.
Next up is law enforcement. I wanted to be as expansive as possible to make the setting realistic. One thing that tends to get oversimplified in both fiction and games is the differences between different law enforcement agencies. I find it more interesting to include more of the layers.
To that end, I start off with the federal agencies. First, there's the Bureau of Investigation (their historically accurate name for the time), which primarily enforces the Mann Act (something TSR glossed over, as they had agents going undercover in bank robbery gangs instead). Then there's the Prohibition Unit (again, using their historically accurate name for 1924), probably the most likely agency to be involved in the campaign. I also make sure to point out the role of the US Marshall's Office and that all of these agencies would be working with the US Attorney's office and the federal courthouse rather than the district attorney / county court.
At the state level, there's the state patrol. Which at this time was brand new and couldn't do anything but enforce vehicle laws on state highways. There's also the local prison, Statesville Prison (which TSR used and is a real Illinois prison; it was also used in Naked Gun 33 1/3 which inspired me to add Rocco Dillon into the mix).
At the county level, I have the Bloomfield County Sheriff's Office (TSR included the county name, but no sheriff's office to speak of). One of the things that drives me nuts is when fictional works conflate local police with the county sheriff's office as if there was only one agency in the area (unless it is a small, rural area where sheriff's office would be contracted for local law enforcement as well). Also included is the district attorney's office, the county circuit court, and the county jail (another pet peeve I usually see - county jails being conflated with state prisons).
Finally, there is the local level - the Lakefront City Police Department. I stick to the TSR setting model of one precinct per ward plus a central HQ. I believe the historical Chicago had quite a lot more precincts than that, but it is difficult to figure out the exact number and this seemed easier.
One thing I don't want to shy away from in the setting is the racism of the times. It's part of noir (the various ethnic groups at each other's throats) and is a huge part of the politics of the time (when eugenics and the KKK were more popular than ever). To that end, I make special note to include that the police have black officers, but they aren't allowed to arrest white citizens (yes, this is historically accurate).
One other change I added was to include the seperate agency for the Lakefront City Park Police (based on the Chicago Park Police of the time), as they are responsible for the various wilderness and park areas where investigators may go exploring.
Finally, I included notes of the private detective agencies operating in the area - the two main agencies from TSR that were real agencies - the Pinkertons and the Burns agency. While not actually in the city, I plan to have an operative from Hammet's Continental agency show up at some point.
As I continue along my setting guide, the next section is Media. I've included the three TSR newspapers from the Gangbusters setting - the Tribune, Star, and Herald Examiner. For the Examiner, I'm recasting it as a bit more socialist / yellow-dog journalism than in the default setting. I also added in a radio station, KYW (a real Chicago radio station).
Then it is on to politics. Politics is a hot-button issue, but is very important in the period so I can't just leave it out. My way of handling it is primarily to note that both sides are pretty much wholly corrupt at all levels and connected to organized crime. Other than that, they are pretty much there to fight about prohibition and unions. There's also a section about the various Socialist parties, as Trotskyites and anarchists fit into some of my planned events. For the local politicians, I'm primarily using the TSR setting NPCs but I will be including the county commissioners and some of the state level politicians as well.
Next up is a large section on recreation. One thing I felt TSR really lacked was to say what people did when they weren't cops and robbering. I have two baseball teams in the area (based on Chicago's teams, complete with one having a recent scandal), beaches, boxing, country clubs, horse racing, jazz clubs, libraries, museums, the opera house, parks, restaraunts, and theaters. Lots of these places will either have ties into one of the criminal networks or be somewhere that more Cthulhuesque investigations might lead.
Along with politics, I also include the hot button topic of religion (avoided completely by TSR). Because religious organizations were so instrumental in the prohibition movement and tied to various ethnic groups, I wanted to include at least some information about them and the big split between Roman Catholics / Liturgical Protestants and the Pietistic Protestants on the issue. I also point out the other religions commonly found in the city.
The next section in my document discussed the local school system and various colleges in the area. Like other sections that fell outside of the normal cops and robbers setting, I had to make things up based largely on historical Chicago. While not going into detail, I did specifically mention several colleges and universities found in and around the city - including art institutes, Protestant bible colleges, and a Jesuit university. The largest one that investigators might use for research and that had ...interesting... collections would be the prestigious North-Central University (a stand in for Northwestern University).
My last section in my setting guide discussed transportation, another area where I based things on Chicago. The city has an elevated train line as well as electric streetcars. There is also a private bus company to take passengers to the outlying areas (Lakefront City Motor Coach Company) and several taxicab companies. Two of the largest are essentially at war with each other - the Canary Cab Company (based on the Yellow Cab Company) and Variegated Cab (based on Checked Cab).Characters
As I mentioned, we haven't done character creation yet. I have talked to the players about making sure we create them together so they have a common theme (for example, we can have a criminal and a cop, but make the cop a corrupt cop on the take who assists the criminal's gang).
One of the players is definately leaning towards a criminal or corrupt politician but I haven't heard anything from the others yet.
My "Player's Guide" book split occupations into a few recommended categories and other occupations (somewhat similar to how CoC usually does it). My top listed occupations were Criminal, Gangster, Federal Agent, Police Detective, Police Officer, and Private Detective. The other occupations I had listed were Alienist, Author, Boxer, Businessman, Clergyman, Dilettante, Entertainer, Explorer, Laborer, Lawyer, Physician, Politician, Professor, Reporter, and Union Activist.
I thought that was a good enough cross section to get people ideas. I also wanted to keep it somewhat limited in order to fit into the setting focus and to make it easier for me to adjust the careers (I kept having to edit them while I refined my skill list in the rules).
Naturally, if a player had a different concept in mind that wasn't on the list I'd work with them to put something together.The Sandbox
So, now that I have set up a basic setting I've been working on detailing out the sandbox environment itself. I'm avoiding going into specifics here, not only to avoid spoilers but simply because everything is still changing as I revise it.
I started with the list of NPCs, listing them out. As I do that, I start to notice gaps and add in more NPCs to fill in the gaps make things seem more "real".
Next, I started drawing some relationship maps. My goal is always to have key NPCs inked to at least two or three other NPCs (I want multiple ways the group might interact with the NPCs). When I start to notice some gaps, I start adding more relationships, which sometimes eliminates some of the NPCs I added. For example, I had a cult member with a daughter who was a dilettante. I also had a completely different branch with a young guy in debt to criminals who was dating a different dilettante and they were trying to get her money. Then I thought, hey, want not get rid of the other dilettante and just make it the cultist's daughter who he's dating?
For key NPCs, I also start sketching out some key locations - where they live, where they work, etc. There's a mysterious mansion out in the country connected to someone, so I start planning it out. Someone else owns a lake house - I decide to put it on a small island and map out the island and house. I map out the Chinese restaraunt in Chinatown where the tong is dealing H, and the corner house where they have their dice games. Etc.
Each location has a list of people associated with it, events that can happen there, and clues that could connect to other goings-on. And of course, any occult or mythos books that can be found - along with the skill gains and sanity costs associated with them. Call of Cthulhu isn't really about fighting monsters and I don't usually include many; that said, the few places where it makes sense I also add in some notes about inhuman horrors there.
Finally, I have my list of big events to happen in the sandbox. Some are just the normal Gangbusters style events related to the city's crime war, mayoral election, and other business. Others connect somehow to the mythos cult activities occuring around the city. Each event notes the people and locations involved along with notes about clues.
For clues, I'm more or less following the Trail of Cthulhu style where there is at least one obvious clue that can connect to either a person, place, or event that the investigators can follow up with, along with multiple smaller clues that might be detected that can give more information about what is going on.
I don't actually have all that much documented out yet for myself, but I like to leave a certain amount of things open as I still want to see what characters the players come up with (I feel it is important to customize at least some of the initial events to get the investigators involved) and I like to keep other things open since the events should change once characters start playing around and causing things to happen.