Summary of the walmart high cost of low prices video?

i have a test in my geography of a changing world cl tomorrow and there are going to be quite a few questions about the walmart: high cost of low prices video. i didnt have enough time to watch all of it, but i have to main premise (walmart hurts small business, is anti-union, not environmentally friendly, no workers rights....) but if there are any specifics from the movie that you think could be helpful or might be possible answers if you could post just some litle facts about that movie that would be great. thanks!