BallRescue is a game I want to finish one day. I first made it in Java using a game library. My experience with version control was very poor back then, so the project somehow got lost. As a result I recreated the game in Unity with an ingame map editor instead of a webapp. The scope and my visions for the project ended up to great so I started losing momentum till it all stopped.
You can read more about the first web-based level editor here: https://bevster.net/ballrescue-mapmaker/
Since I lost the source code I ended up recreating the game in Unity, this time written in C#. Under is a video from the in-game level editor. The thought was that users could make custom levels and upload them so others could play them. The project did not go as far unfortunately.