Yoshinori Ono, the director of Deep Down has recently tweeted that the game development is making a steady progress on PS4. In his last sentence in japanese he mentions "a solo mode" (google translate: Deep down and steadily (provisional), ongoing development! PS4 version of solo play has been able to. The ~ I wonder if I can soon show off in front ...).
He also posted a pic of Blanka toy and a Dual Shock controller in front of a flat screen with the game running on it.
All of this may lead to these conclusions:
- The game is a PS4 exclusive and is being developed on it only (The game site only states Playstation 4)
- The game has a solo mode and an online/multiplayer/coop mode with the solo mode being developed first.
-The game on a flat screen and his last sentence tease an announcement/presentation in the near future.