The most important event in December was the launch of Steam Early Access where you can buy and play the game and support the development for 36,99€.
Then in connection to the Steam launch the NDA has been lifted. Money already gained through the sales allowed to hire more people to the team.
December became a month where the bugs were hunted and killed as a primary focus. However in addition to the insects mass murder new graphics configuration options was implemented and botting auto-detection systems are in place.
Of course many more updates came to the game and you can read the whole list here.