Version 1.65 Hidden/Secret Areas

Hello all! I've been digging around for information on some hidden areas in version 1.65 of Rabi-Ribi, and so far I've come up with a video of Rabi-Ribi Ravine 2, and rumors of a hidden area in the Hall of Memory past Miriam. In version 1.751 of Rabi-Ribi, there have also been hidden rooms added to the Starting Forest and Exotic Laboratory. Does anyone have further information on any of this? Hopefully this discussion will be of use to those seeking information on the hidden areas of Version 1.65 and 1.751.
Also, here's the video: