Glad you liked it! It's still going, with new owners :) I'm revisiting the map generation because the authors of RotMG are working on a new game, and have asked me to work on the maps.
- https://github.com/redblobgames/dual-mesh/
- https://github.com/redblobgames/mapgen2/
However the html5 UI isn't (it's a big hack I'm abandoning, and working on a different version). Feel free to View Source if you want to see the ugly UI code :)