The Octodad Editor allows you to create levels to submit to Steam Workshop. The editor is Windows only for the foreseeable future. It is the same editor we built to create the story levels in the game. If you are comfortable using an editor such as Unity or UDK, you should be able to figure out how to use our editor.
In order to learn about how to use the editor, please visit our wiki:http://www.octodadgame.com/workshop/index.php?title=Main_PagePlease make sure to read 'Setting Up Your Level' guide thoroughly, since failure to setup your created level in the correct place can cause issues with submission and loss of work.
The general design behind levels are that trigger objects check against conditions and trigger event objects perform events. You can create chains of logic so that triggers must be active before other triggers. Feel free to open existing levels in Content/Levels/ folder of the game for reference or Content/Levels/Test/ for examples of simplified actions. All existing assets in the game can be used in workshop levels, as well as the ability to package in your own as long as they are in the same working directory as your mod.
Since our primary focus has been the release of the game, the editor has a fair amount of bugs left to fix, so we would definitely appreciate any and all bug reports to help us improve the editor and its usability. We hope to expand the wiki and create videos/streams of how to use the editor over the next few months as well.