Trailer:
http://www.youtube.com/watch?v=9UvYWMSRAVo

Here info from Ign :

3D Dot Game Heroes is set in the Kingdom of Dotnia. This world was once made up of 2D sprite art like something out of an old school game. However, wanting to attract more people to the kingdom, the king decided to use technology to make everything 3D. This is where something goes horribly wrong, although just what that is has yet to be specified.
Despite the retro theme, the game does look impressive technically. It's being developed by Silicon Studio, a developer who worked with From on PSP's Onore no Shinzuru Michi wo Yuke, but who also does middle ware.
In line with the visual style, 3D Dot Game Heroes has some traditional RPG themes. The game's background story involves six magic orbs which were stolen by a demon of darkness, who was then defeated by a brave swordsman and sealed away using the combined power of the orbs. You play as the grandchild of that brave swordsman, and you're tasked with saving the world.