Free DLC is being offered to compensate for the delayed release of the game.
Dead or Alive 5 Last Round's PC release date has been delayed until March.
Looking on the game's Steam store page it now lists the new release date as 30th March.
An update to the store page also reveals the reason for the delay is "to provide you with the best experience possible". Because of the delay the game will come with the Halloween 2013 Set completely free to those who buy the game on Steam, "in appreciation for your patience".
The update also states that the online modes for Dead or Alive 5 Last Round will be added to the game via a patch within 3 months of release.
It currently looks like the console versions of the game are unaffected in terms of release date, so assume they are still on schedule for their 17th February launch.