Gotham Knights is coming out an entire four days earlier, for some reason

rockpapershotgun.com:

It's not often that we get to report a game coming out earlier than planned rather than delaying the date, so it's nice to be able to tell you that Gotham Knights has moved its release date up. It's only by four days, though, to October 21st, which is sort of baffling. Maybe Warner Bros. are about to announce a new DC-verse TV show coming out on the Knights' original release date of the 25th? Who knows. But along with this early-release sneak attack is a new trailer, giving us a closer look at the rogues gallery that the extended Bat-family are up against.

Bats himself isn't in this game, leaving a newly vulnerable Gotham under the protection of a clutch of his protégés: Batgirl, Nightwing, Red Hood and Robin. As well as run-of-the-mill thugs Gotham Knights has a most-wanted list of some of Batman's classic villains. In particular, this video confirms Harley Quinn and Clayface (and I think it's Clayface you can hear saying, in voice over, "This biopic is based on a true story - my story!", which is objectively very funny villain patter). It also appears that Mr. Freeze has made himself a spider-mech. I'm glad for him, pleased he's thinking big. Previously we've seen a peek of Penguin and the Court Of Owls. That's a lot of supervillains.

Luckily a leak earlier this year indicated (and it was later confirmed) you can team up in four play co-op to BIFF! and WHAM! your way through the game. If you're after a closer look at how being a hero plays, let me point you in the direction of this more in depth video on Red Hood and Nightwing's fighting styles.

Of course, none of this offers any indication on why the release date has moved four piffling days. At the time of writing, the date hasn't even been changed on Steam.