Can't find the secret area. I did manage to get myself stuck outside of the map area. If you go to the upper right corner of the upper square green room it is possible to jump up from there off the screen up and to the right and you end up outside the map in a 2 room empty space right above the large green rectangle room.
Did you find the cave with the tombstones? (It's only a secret place lore-wise, in-game it's pretty easy to find. But this place does have a secret.)
Thanks for reporting me that bug. I reproduced it, and I will be able to fix it for the next version. (If you restart the game, you will be sent back to your last save point, so you should not be stuck forever.)