Since the previous thread was deleted, I decided to recreate it so that people know where they can find custom levels and the status of Workshop support.

The developer of this game has said this about custom worlds/levels and Workshop support for EG1:

MagicalTimeBean님이 먼저 게시:

Workshop support was going to delay the game too long, and since I still have EG2 to finish this year, I held off on it for the time being. You can find and share levels at http://www.magicaltimebean.com/forum/index.php?board=3.0

He's also said this about possible future Steam Workshop support for EG2:

MagicalTimeBean님이 먼저 게시:

For EG2, this is something that's planned, but version 1.0 will not have the editor included, because I need to get that up to speed before releasing it. It will be in a 1.1 patch, and Steam Workshop integration is possible, but not guaranteed. More details on that soon...

In the meantime, to install the levels in the link above, just drop the .maaap files from the threads straight into your \My Documents\Escape Goat folder - they don't need a separate folder. The next time you start the game, you'll be able to select the new world just like any other. I was confused about this too, so I hope this helped somebody!