Rising Star Games has confirmed that Zombie Vikings: Ragnorak Edition, the PS4 physical edition of the game, has been delayed until Q1 2016. The decision has been made after there were some issues with the digital release, though many of those have been addressed with patches. More updates will be released by Zoink, the developers of Zombie Vikings, over the coming months to address any other issues that crop up.
The Zombie Vikings: Ragnorak Edition will feature two extra playable characters, Frostbjörn and Raybjörn, as well as five extra versus arenas. A digital artbook will also be part of the package. A few weeks ago Zoink revealed that Zombie Vikings released with bugs because of the Vote To Play deadline that had to be met. You can read our review of Zombie Vikings here which despite some issues is a fun game.
Source: Press Release