Steam Workshop is open. There's a level editor in the game now, and levels you make can be published straight to the Workshop — with a picture of their map. Anything you subscribe to turns up alongside your own, ready to play.
You have to beat a level before you can publish it. It's the only thing standing between the Workshop and a pile of levels nobody can finish.
The block editor keeps its zoom and position when you switch views. Going full-screen used to zoom you in and refuse to let you zoom back out as far.
Smell no longer reaches through walls it can't get round. An apple sealed in a room with no way in isn't smelled at all; one you can reach the long way still is.
Opening a level starts you at the Start block instead of wherever the last one left the canvas.