They're currently doing a "Build Challenge", which sees you building a Flying Coaster. The restrictions in place are build area and budget, but the rest is up to you. If you submit it to them, your design may get picked to be a default blueprint in the next game update. What a fantastic idea to really get the community involved in the development of the game.
When building coaster tracks, you now have access to new slope options to further customize your rides. They also added in some science fiction building pieces and props, along with some tweaks to guest behaviour and bug fixes.
They also have an experimental beta up on Steam, which uses a new version of Unity and they are asking for feedback on how it runs. Read the full changelog here.
It's still quite early in development, so it's not quite the experience you might want just yet. It's impressive for what it is though and their regular updates are great. The interface is extremely clear, building is incredibly easy and all the little details make me really love it.
The best thing about it for me, is seeing all my lovely guests actually get onto the rides and use them, the simulation behind it is fantastic. Seeing individual people climb into a Bumper Car and then drive it around, seeing them woosh down a Spiral Slide and then walk off — extremely satisfying! It's almost mesmerizing watching them fly around on various roller-coasters, seeing them fly underground and pop out the other side.
For those of you missing the days of Theme Park, this is likely an ideal game for you to look into. Constantly reminds me of it and that's awesome. So great that Linux has games like this, which can end up being a real time-sink.