Well quite a lot actually!
They have added 2 companions a lot of bugs fixing and
For now they are working on Hardcore Mode,implementing new skills,balancing encounters,Linux version,rerwriting of some dialogs, because sometimes it was really hard to understand where to go next,core optimisation,gold re-calculating for some items,and if I understood correctly in the last Kikcstarter update Farhang Namdar said that he works on "the dual dialogs"