So the plot is that the main character learns how to lie and no one else knows how. So he goes around saying whatever he wants and everyone automatically believes everything he says. Now, his mother is about to die and she comments how death is no fun because its an eternity of nothingness (though, if you believe in no after life, how would you experience that?). So, the main character lies to her that there's an after life (which makes her happy) and everyone else in the hospital over hears him, and get interested. People then show up at his door asking about what happens when you die, so he comes up with religion. The the tenets of his religion are as follows:
1. When you die, you get a mansion and unlimited Ice Cream.
2. If you do three really bad things, then you go to a bad place and don't get Ice Cream.
3. All of this is decided by a man in the sky. He's responsible for everything that happens on earth, good and bad.
Everyone just believes this without proof. People stop finding pleasure on earth in because they're looking forward to their mansion and Ice Cream. So on and so forth, and you get the idea.
A couple of observation should be made about this. For one thing, the writer of the film (a British comedian) knows about as much about religion as I know about quantum physics. What's even more annoying is that he thinks he's being very provocative when he doesn't understand his subject material. Again, it would be like me coming up with jokes about physics or chemistry- they probably wouldn't ring true to scientists. But on top all of this, it's not very original, in fact, it's just the old Epicurean critique of religion.
The Epicureans claimed that we were all made out of atoms that randomly flew together. The gods were off in some other realm enjoying themselves and paying no attention to what's going on earth. Therefore, anyone who claims that the gods have spoken to them are lying and trying to take advantage of you. Their impeding your ability to fulfill your pleasures here on earth. So reject all religion and simply gain your pleasures here on earth, because when you die, that's it. You were a bunch of atoms that flew together and that's what you're going to turn into again.
In the 17th century this thinking was revived and has determined modern culture. Darwin was influenced by it- in fact his grandfather was an proponent of Epicureanism. Marx has obviosu signs of this thinking as well. Spinoza used it to invent modern Biblical scholarship- think about it, how does the historical critical method work? Does it provide much evidence? Or does it just go through Biblical texts, assume that they are made up of fragments of different priestly or other groups trying to make power plays and then stitched together in one big power play? Is there any evidence of this? Of course not! But that's how the HCM works. It simply interprets reality on the basis of this Epicurean view of how religions "must" develop and there you go, you've got your new "scientific" reading of Scripture.
In the end Epicureanism might be able to critique the religions of fallen humanity. If they are the product of sin, what else could they be than a power play? But this is not the meaning of the Biblical witness, which centers itself in the gospel. Epicureanism is in the end unable to explain the gospel. How indeed can the gospel be a power play? It is God's own self-surrender to us in the form of a unilateral promise. It is not his power over us, but his surrender to us. What it creates freedom and not enslavement. Furthermore, this freedom is freedom to enjoy our life as creatures and not go off to some other realm. The final eschaton will not be an abrogation of life on earth, but rather be a fulfillment of it.