Entertaining and to me - plausible conclusions with, to me, an appropriate amount of room for arguments of speculation and or dismissal of anthropomorphizing. If you like archeology like me it was easy to enjoy.
When the heavy guy went in and they started enlarging the opening for him I was dismayed, may as well tunnel in and make a door. They only chipped off some rock so it wasn't that bad, but I fear they moved a lot more than what they showed so he could fit through the crevice.
Another item that bothered me was making it seem he made some discovery of etchings in the wall his first trip in. If researchers had been on site for 8 years - I find it really hard to believe nobody noticed glyphs on the walls before he got inside.
Overly long? yes but still entertaining.