For our game, Shadow Rush, we also built an editor. And honestly, the editor went a bit out of hand. Our artist made it entirely by himself and it looks absolutely amazing. It definitely took a lot of time, especially the "loading the map into unity" part, but it helped us when we had to design the maps.

The editor is online, you can check it out at https://shadow.jossafossa.nl/

In the bottom right you'll get a string, which you can paste into the game's import screen!

Happy playing (with all games, not just ours)