There's been a few interviews in the press, like this one at RPG Vault.
Vince D. Weller: You can play The Age of Decadence in many different ways - fight your way through the game; walk in shadows, looking for less traveled roads like rooftops, walls, and locked doors; use the power of persuasion and personal magnetism; let your faction open doors for you - "Why didn't you tell me you were with the Corleone family?"; or play as a con artist, impersonating other people and preying upon the gullible.
What kind of gamer will it appeal to? Most likely to those who feel that role-playing games could use some role-playing these days, and that there are other things one should be able to do in an RPG other than killing things that exist for no other reasons but to be killed.
And to answer the last question, I'd say the length is about 30 to 40 hours, and as for replayability, due to the non-linear and multiple-solutions nature of the game, you can replay quite a few times without repeating what you did before.
There's also interviews at RPGDot and NMA.
So yeah, I'm basically pimping a friend's project, but it's one I believe in and will happily fork over my $25 for it when it's released. And if it sucks, at least I know where the guy who made it works.