If you look at the video for the game jam and the art that's created it sort of gives me the impression its going to be a 2d crayons coloured theme.
That's just because of the way Blackthornprod paints, I think.
Ehhm I don't think they will want a theme that will limit us to only 2D.
Aside from that I agree with Schred.
Blackthornprod made the trailer and thats his art style