Back in the late 1980's I created a superhero campaign we called "Saviors." I say created because it was a bit before I took over running and plotting the full game originally Eric Ferm and I built up the background and then my sister, Cat came aboard. She added a lot of great material and ran some dynamite games for it. Eventually a number of things, including my desire for greater control, moved me into the driver's seat of the game. That's a story for another time. For our group it was the first of the grittier games. We were in the midst of or just finishing Watchmen, The Dark Knight, Miracleman, Miller's Daredevil, and the other like-minded more vigilante oriented comics. The game was uneven, but fairly successful and some great moments came out of it. The actual campaign itself had several major turning points which dramatically shifted the narrative and course. It also had the largest number of character fatalities of any campaign I've run. A few years after we finished it, I ran a fairly long-term sequel campaign which took as its starting point proto-Cyberpunk ideas. I like some of the concepts of Cyberpunk, but always thought it set itself too late-- that the actual impact of the introduction of the various technologies was more interesting. As a whole, I liked that "Saviors II" game. Much later I tried to do a reboot of Saviors, but it didn't hold together as well. using Champions when other, more accessible systems existed and the change in available technologies made the game a little less interesting.
Kenny and I were talking about the difficulty of doing a real low-level crimefighter game in today's environment. Public reaction to anything falling outside the norm, severely increased public surveillance and certain technologies (cell phones, internet) really change the narrative options a gamemaster has. Still, I think there's some material there worth salvaging. I enjoyed Kenny's brief SWAT game and I've about doing one myself. But what struck me is how really rich the setting provided by Gotham Central is. I have the first three trades of that series and had been rereading them as part of my breaks between writing spurts.
I like the idea of a police procedural game, but one in which the players have extra leeway in terms of being detectives, forensic experts, and even SWAT. My original thought was to do something that was more weird-- a kind of Delta Green-based police game. But the more I think about it, the more I'd like to anchor it in the real world. The special case unit handles anything that even beings to smack of supervillainy or strangeness. You could keep the real "named" figures off-stage for a long time, with the players dealing with the marginal characters in those organizations-- the middlemen, henchmen and suppliers. Then when and if the actual Bad Guys appear, they'd be more menacing and threatening. There'd also be the question of how to deal with vigilantes. I wouldn't want something as stripped down and, quite frankly tech-love sci-fi, as the recent Batman film. Instead, I'd probably have a richer universe for the characters to operate in, with a blend of known existing figures and some new ones. Adapting the Batman rogue's gallery would work, since more people are familiar with them from at least the animated series.
I'd probably use a modified version of Gumshoe. The investigation system in there is excellent. However, the challenge resolution system sucks and irritates players. We used it a couple of times (for Gaslight Gumshoe, Spies and Super Detectives games) and the general consensus among about a dozen players is ditch everything but the investigation rules. I'd probably use something like Gurps or True20 to handle that side of things. Not that I'm going to get around to running that anytime soon, but it is something that struck me and I wanted to remember.