The film is based on the script of Shyamallan, shot not by Shyamallan, but with Shyamallan in one of the main roles.
Unlike the future fantasies of a famous Hindu-American, the Devil does not contain as many internal contradictions as the same Knock in the hut. The film is chamber, shot interestingly, there are no extra characters, in suspense, it is interesting to find out what (although, rather how) will go wrong.
There is almost no outright idiocy to promote the plot. There's no moral. For 2010, this movie could have been something new.