Gotham by Gaslight - aka Victorian Batman vs Jack the Ripper - was a big deal for comics back in the early 1990s, what with it both transplanting Bats into a new setting and being a self-contained tale rather than the usual unending episodic fare. Sadly it's been largely ignored in this modern age of ultra high-tech Batmen and Grant Morrison miring poor ol' Bruce in endless, obtuse fantasy stories about nothing, but a few years ago Day 1 Studios were set to make a videogame based upon this 19th Century superhero. You'll know Day 1 from FEThreeR, the Xbox MechAssault games and the upcoming PC multiplayer mech title Reign of Thunder, so their heritage perhaps isn't really in the vein of the quiet, thoughtful oddness of GbG.
Whether or not they'd have pulled it off is something we'll never know, as it was canned before development started in earnest - but a leaked proof-of-concept animation trailer does suggest it could have been an especially atmospheric steampunk odyssey.
A low-tech Batman in a two-centuries old Gotham, coming off like the glorious bastard son of the Arkham games and Thief. I'd have loved to have played this, partly because the Victorian superhero idea is appealing, partly because anything with a city to explore tends to attract me, and partly because I suspect it would have sidestepped the more openly fantastical elements that the Arkham games somewhat akwardly embraced.
This was unearthed by Siliconera, who have grumpily blocked embedding on their original copy of the video. Youtube to the rescue, as always.
That is one fluttery cape. Not sure whether this would have received a PC release, but it's sadly academic now. It's Arkham games for the forseeable future. Although given the ending of Arkham City, a series reboot to another timeline would be one way to bring all the major players back to the fold...