`` Monsters vs. Aliens '' about Earth-born `` monsters '' taking on megalomaniacal alien . The movie is based on the novel of the same name by Robert A. Heinlein. `` Monsters '' has great talent but no script to speak of , says Tom Charity .
`` Monsters vs. Aliens '' about Earth-born `` monsters '' taking on megalomaniacal alien . Film 's main character is almost 50-foot woman voiced by Reese Witherspoon . `` Monsters '' has great talent but no script to speak of , says Tom Charity .