At the Capcom Online Games conference today they confirmed that Deep Down is an online game, and will be featured at TGS 2013 this year.
More specific info:
Originally Posted by Siliconera
Capcom is about to reveal more about deep down, a PlayStation 4 game first teased during Sony’s hardware reveal. deep down is being developed by Capcom Online Games and as expected is an online enabled RPG that supports a large number of players. The game’s genre is a “memory reading RPG” or “reading RPG” as see in katakana. The teaser site also mentions deep down requires an internet connection and is an online exclusive similar to Dragon’s Dogma Quest.