When Noah's boy meets the lonely girl in the artificial valley covered with death there are certain scenes showing the walls. Those walls are carved with traces and are so even and somehow polished that they can only have been made by digging machines and not by shovels or what ever low tech tools are shown to exist in the technology of the movie.
When Noah is praying on the roof of the ark, in the short shots, the water is deep and directly in front of him. In the long shots (especially from above) he is in the center of the roof, and the water is nowhere near him.
When Noah is looking out of the ark towards the forest because he hears the animals coming, the sun is coming up over the trees and his head is blocking some of the light. But when we see him from the front in that same scene, there is no direct sunlight on his face or in the background. It switches between the from behind to the front view a couple times and this stays consistent between them.
All the animals are sedated and are all seen lying down. An elephant normally only sleeps for about four hours a day. If an elephant were to lie on its side for more than a day (for example) the weight of its internal organs would cause them to rupture and fail.
At the end of the film, Noah walks up the valley towards his wife and his knees are clean. Just before he kneels down with her, there is a close-up of his knees which are now dark with dry stains around them.