Factual error: Al plants a vegetable garden. 6 weeks later his garden is shown with fully developed vegetables including full stalks of corn. Not possible in a month and a half.
Factual error: The final scenes titled "Kankakee 1991" show desert scenery in the background; Kankakee, Illinois is in the Midwest US, which is almost entirely grassland and no desert.
Suggested correction: Kankakee and most areas surrounding have sandy soil and some areas can look very desert like during a very hot dry season but the mountain in the background is what gives it away. Kankakee is very flat other than the landfills.