Alright here a couple spoliers for the updates :D
All taken from here
(Not everything will all be in ONE update there will be MANY)
- Customizable Christmas trees with animated lights.
- A pet elf (touch screen's)
- Zombies in elf and santa costumes
- Slimes in gift and ribbon costumes
- Festive Grappling Hook
- Festive Wings
- Eggnog, an 80 HP health potion.
- Candy Cane hearts (much like the Candy Apple hearts of Halloween)
- Red Potion that gives you every buff for an hour and heart sprites
- A Candy Cane sword
- Ruldolph, a flying Reindeer Mount summoned by the Reindeer Bells. The antlers will also be varied.
- Santank, the Christmas boss who will drop said Bells.
- An extra Frost Legion member
- The Lunar Boss.
- The SDMG
- The SteamPunk Wings
- Lots of bug fixes.
- Professional language translation.
- A buff to the Golem
- A Portal Gun
- Alternate Underground Theme music.
- New harder world types:
- Alien planets
- Alternate dimensions
- Evil worlds
- Enemy factions that will move into your world, and build their own city.
- More events
- Lunar Event
- More/improved invasions
- Official Modding Support
- Farming and stamina system that gives a bonus to player stats.
- Implementation of Steam features
- NPCs which can give quests to provide more content.
- New items
- Fishing Pole
- New furniture:[tweet 1]
- Weather Vane
- a wall mounted fish
- Window with Curtains
- Cuckoo Clock