The game was updated with some new features today, that's probably why.
EDIT: Seems it was yesterday.Link
(Steam Community Forums.)
New engine, implemented by Abstraction Games. Should fix many technical issues and make the game run faster for everyone, and it'll enable us to develop Mac and Linux versions next.
Steam Workshop added, for browsing and sharing user-made levels. Yes, we listened to the 1,779 post petition you guys started even after we'd already announced we would do it.
Option to turn off swearing. Up to you whether this makes "Grow a ####ing #### and shove it up your ###" kid-safe.
Reconfigurable keyboard controls.
Vertical sync option. I didn't know we needed this, but the folks at Abstraction added it and now the animation is at least 23% more beautiful.
Level editor. The level editor has been in there since launch, but some people still ask for one so I'm just going to keep announcing I've added it until everyone knows it's there.
You can now place multiple elevators in a level without it crashing. That's more than I could do when I was making the game, so I expect your levels to be at least twice as good as mine.
If you have any technical troubles with the new version, you can still use the old one by going to Properties > Betas and selecting 'oldversion'. Post your issue on the forums too, so we can fix it.
//[Edited by LordJB, 6/18/2014 7:37:46 AM]