The correct definition of "Level" to use, in the context of the shape of the earth, is the definition that land surveyors use. That definition is "Everywhere orthogonal to a plumb line.". In other words, 'Level' means 'Curved'.
Level also is different at all points on the earth. Level is always perpendicular to the earth's core, its center. The earth is spheroid. This fact has been known for over 2300 years. This movie is far from a documentary. It is baseless drivel produced by charlatans that are part of the flat earth cult.