Well now we know what 13AM Games was tweeting about this whole time.  They have officially announced that Runbow will be getting its first batch of DLC this week.  You can check out the full breakdown below, but the DLC will include new costumes, a new guest characters, single player campaign, and multiplayer maps.

They also announced the game will be on sale for the next two weeks to celebrate the release of the DLC.  You can also check out the official Runbow store, as well as purchase the soundtrack (composed by friend of the site Dan Rodrigues).