One of his films that I thought was interesting is Limitless in which he plays a struggling writer who is unable to write a book that sells until he takes a mysterious drug that radically boosts his cognitive abilities. In the process he can write very impressive books and becomes a renowned author. When he loses the drug, however, he is temporarily unable to continue writing and his career is in jeopardy.
He eventually takes it again and is able to somehow replenish the drug so that its effects don’t go away. Although the scientific accuracy of the film is questionable, it explores interesting themes related to the possible side effects of human enhancement as well as true human potential.
He also does a good job at acting the role and makes a believable dramatic transformation when he goes from the struggling writer who is out of ideas to the confident genius as a result of the drug.