Unfortunately no, I haven't gotten the 3rd ending. I was thinking that maybe it was only in the Steam release as I was playing the original Darkling Room version so I Installed the Steam version, same result, no 3rd ending. I must have completed the Saxton Map puzzle correctly though since
Became so frustrated so I found a YouTube video of the 3rd ending so at least I won't miss it.EDIT:
I got it now, it was there the whole time...I had assumed that to get the 3rd ending I had to
All in all, a very well done game, certainly not a short game. The whole thing reminded me of a combination of DarkFall, Barrow Hill and the Lost Crown games.