In the "as seen from inside the cave" shots of the guys climbing down the rope and into the cave, the overhead entrance is much larger than the hole exposed by the stone cover-tablet that they'd pried out of the ground a few minutes earlier.
When the second guy is getting ready to descend on the rope into the cave, the shots of him as seen from within the cave show him starting to "back-walk" down the slope using the rope to steady him, yet in the interspersed "outside" shots seen immediately after each of these "interior" views, the guy is still just at the stage of merely testing how solid the rope feels before starting down towards the cave's entrance.
In at least one shot of the five men climbing up the rock towards the summit, none of them is carrying the hank of rope.
Four of the guys lift and carry the mummy from the truck into the barn, so it is supposedly very heavy, as such a large humanoid with a solid mud covering presumably would be. Yet the next moment, only two guys are carrying the mummy when they bring it over into the corner and set it down on the trunk, and they aren't even straining to hold it up, so it is obviously very light.
At around 20 minutes when the two guys going fishing see Bigfoot in the road. Larry is seen carrying a stick and then a few moments later he does not have a stick and then it is in his hand again a few moments later.
The mummy was in a side-chamber that was some distance from the vertical entrance-shaft, so there would not have been much light on it, and certainly not light from above, as it is shown to be illuminated when the guys are examining it.
The early scene featuring the black dog is clearly intended to take place at night. Cricket sounds are heard, a filter is used to darken the image, and the actress makes reference to it being night. But the opening shot of the scene aims the camera right into the sun!