A month out from its planned July 29 release, Warner Bros. has delayed Batman: Return to Arkham. The title, which includes remastered editions of both Arkham Asylum and Arkham City for PlayStation 4 and Xbox One, has strangely not been given a revised date. The reasoning behind the delay, according to the official statement, is to ensure that its a polished Batman Arkham game experience.

The announcement was made via the Warner Bros. Games forum.

After reviewing the progress of the project, the team at WB Games has decided to delay the release of Batman: Return to Arkham to give the team at Virtuous Games additional time to deliver a polished Batman Arkham game experience.
We do not have a release date yet and will be sure to communicate that once we are sure the game will be ready.
We know this is disappointing news, but we feel the extra time will allow the team to create the best gaming experience for our fans.

As mentioned in the post, development on the project is being handled by Virtuous Games and not Rocksteady, with both titles being ported over to Unreal Engine 4. Here's the announcement trailer from a while back.