Gotham City Impostors couldn't be trusted to operate entirely how it promised. The Xbox Live version isn't set to launch until tomorrow, but today more than 100 DLC items are available in the Xbox Marketplace, ranging from 80 to 320 MS Points. All of the items are cosmetic and won't affect gameplay in any way, Monolith tweeted, and all of them will be unlockable in the full game.
We assume it could have been worse -- getting access to optional DLC before a game launches is better than getting access to required, paid-for DLC months after a game launches. So really Gotham City Impostors isn't such a bad guy after all ... oh. We see what you did there, Monolith.