Anime tends to utilize a much more minimalist style. For example, there are less frames per second in anime than there is in standard American animation (which accounts for the much more jerky movements). Facial features appear homogenized, such as the standard small nose and mouth and uncommonly large eyes. Expression tends to be minimal, though there are moments - usually comical - of over the top facial contortions. The themes explored tend to be bleak.
Anime can appeal to adults or children alike, depending on the series or film, but I've never seen storylines in U.S. made series that are as complex or convoluted as some of the most popular in Japan. American animation tends to be silly, absurdist, or satirical - anime has the capacity to explore much darker and dramatic territory.