Yeah, it was really tricky, I had to start again like 5 times!. Then the next one was like you describe, just one colour, one entrance at the top one exit at the bottom :-)
It's being DDOSed. Too many users. Too many submits. The rendering code is light enough on the server that it still works (most of the work is client side, the sever just serves a bunch of json files), but the submitting code definitely crashes.
Cool, but it's now impossible to submit anything, as the server is being DDOS'd. Not out of malice, mind you, there are just too many geeks out there, and this is a Sunday...
Still, one can read the titles of the already posted rooms with: