Thanks narkfestmojo for the level and comment here

I played the map for the first time just now and noticed the room up there, but assumed it wasn't reachable. Off to have another look!

I liked the Ratman Den's in the main game, it was really fun looking for them.
That sense of discovery, like you are somewhere you shouldn't be... adds to the replayability.

Thanks a lot for playing my chamber and finding this, when I published it I expected someone to find the secret room immediately, 4 years on and this is the first time anyone has ever mentioned it lol.

- Thanks