Okay, this is another take on Raj Kapoor's Awaara not in the story or the script, but more in the concept of nature vs. Nurture which is really quite corny by now, and it is even handled very poorly. The idea that a criminal would try to outsmart life by switching between his child and the child of an honest man, just to have his biological man become a decent man, is really quite silly. Not only that, the morale of the story, unlike in Awaara, is the most distorted there can be: it's all in the genes, decency or lack thereof. I can't think of a worse message to convey.
Indeed, the film doesn't work and not just because of its poor story but basically its poor script - it fully adopts all the ingredients of mainstream Hindi cinema - melodrama, sentimentality, unconvincing, childish dialogue, ridiculous action, whiny background score, caricatures for characters, and just a general lack of credibility. Directed by Randhir Kapoor, Raj Kapoor's eldest son who bears a striking resemblance to his father but never matches him in neither looks nor talent. The only redeeming in the narrative is the wonderful music by R. D. Burman.
What this film has going for it other than the lovely music is Raj Kapoor, who finally plays a man closer to his actual age, without the silly shticks of overdone innocence that his characters had become so famous for over the years. He is amazingly kind and wholesome - the kindness in his eyes makes it really work well. Everyone else in the film is a caricature - Randhir Kapoor hasn't got what it takes to lead a film, Rekha gets a role of zero importance, Prem Nath is very poor, so is Narendra. Sadly, Dharam Karam is the most stereotypical film you'll find.