Hotline Miami 2’s latest update has been pushed out he door and it includes the final release of the level editor. The Dennaton team posted:
If you experience any issues with this latest update, please report them in the pinned Bug Report Thread in the Level Editor forum. Additionally; should the latest update cause serious new issues on your machine, we have also set the previous build (v1.05) live on the ‘no_editor’ branch. Use that to opt-out of the editor update while we look for a solution to the problem.
Thank you so much for your patience and help over the extended development of the level editor. Without your passion, help, and feedback this would not have been possible. Now please go make Hotline Miami 3!
There are supposed to be patch notes in the Steam forum but they have not been posted yet for some reason. Keep an eye on the Steam discussion forum as they might appear soon.