That date turned out to be 2 August, but only refered to the first episode. Now there's word of a second episode, "Children of Arkham" on 20 September. This will be for PC, PS4 and Xbox One. Other platforms will come later.

Batman Telltale Episode 2 Children of Arkham

The following three episodes will arrive over the next few months. If you'd prefer to buy the Season Pass Disc in retail stores rather than downloading the first episode to your console, computer or mobile device online, you'll need to wait until 16 September. You'll still only get the first episode to begin with, but you will get access to the further four episodes at no extra cost.

Batman Telltale

Telltale Batman Series: Episode 2 details

There’s been no shortage of Batman games, with LEGO fans most recently having LEGO Batman 3: Beyond Gotham to sink their gaming teeth into. (There’s also a Lego Batman movie coming out next year.)

If the Wiki page for Telltale Batman is to be believed, the second episode's plot will go something like this: "An old friend becomes a new adversary as Bruce learns more about the Wayne family legacy and Batman escalates the fight against crime and corruption throughout Gotham."

There are already descriptions for the remaining three episodes too:

Episode 3: With Gotham on the brink and Bruce under fire, a new generation of supervillains rise and threaten to overturn the traditional institutions of power.

Episode 4: Bruce and Batman must forge alliances and fight old rivals to protect the innocent and keep Gotham from descending into chaos.

Episode 5: The battle for control of Gotham reaches a fever pitch as Bruce discovers a renewed sense of purpose and Batman finds himself pushed to the limits in a desperate effort to restore order.

Batman Series - Telltale games - release date gameplay rumours

Like other Telltale games, the new Batman Series will focus as much on Bruce Wayne as Batman. Also, decisions you make as Bruce will have a “critical impact” on what happens when in costume, and the same is true in reverse.

You’ll also get the choice in various situations whether to appear as Bruce or Batman, “with consequences for both sides”. Also, characters close to Bruce in his private life will have their paths altered towards “corruption or redemption” based on your choices in the game.

The game will be set in the modern world and won’t be tied to the storyline in comics, films or other Batman games. Plus, you won’t necessarily see Robin, Nightwing or other characters: 

Confirmed appearances include Alfred Pennyworth, Vicki Vale, James Gordon, and Renee Montoya.

If you’ve played Telltale’s Walking Dead you won’t be surprised to hear that Batman is going to have a comic-book-style presentation, and the artwork will take inspiration from the works of over 75 years of artists such as Jim Lee, Greg Capullo, and Neal Adams.

The team also revealed at SXSW that it will have a M rating (likely to be Pegi 18 in the UK) and the "cinematic approach will feel more akin to an R-rated film".