There are certainly enough connections in the novel, but I don't necessarily think this allusions are made distinct or clear in the varioius film versions. Whilst of course depicting Simon as a vague Christ-like figure is easy to pick up on, it is not necessarily clear that the rest of the movie has any particular Christian overtones, apart from thematic links to issues such as evil.
Neither of the movie versions I have seen of Golding's novel make any particular connections to Christianity, it seems to me. The novel, however, is clearly connected to man's flawed human nature and our need for a Savior. It is an incomplete allegory, for it shows only the deprivation of unchecked human nature and does not offer much hope for the salvation of man.
Golding's allegory finds a connection to Christianity in its examination of the inherent in evil in man as a ousted from the Garden of Eden. When he returns to this "Eden" in the form of the beautiful island, the paradise is corrupted by the presence of the devil, Beelzebub or "Lord of the Flies." This formidable presence exerts itself upon the innate propensity of humans to be evil, and it is only the saintly Simon (ironically,the name of the disciple of Jesus, Simon Peter, who denied Jesus three times) who identifies the "beast" in man. He then becomes a sacrificial victim, himself, to the devil.
The novel itself is quite compatible with Christianity. The idea of original sin, or innate evil, is prominent in the novel, and is a fundamental concept of Christianity. The natural state of man, according to Golding, is that of a savage. He is flawed, easily tempted, and prone to violence. The boys begin to grow more afraid, quarrel, and break into factions, but Simon emerges as the Christ-figure. He is a messiah--he knows the truth of the literal and figurative beast; he is a prophet--predicting his own death; he is a martyr--he dies explaining the truth of the beast. Evil is more powerful than good on the island, just as it was when Jesus was crucified.
But if this were really completely a Christian movie, you would think that there would be more of a positive moral message.
In the book and the movie, you do not really see any sense that good will win out over evil. The idea that good wins out in the end is a basic idea of Christianity and I just don't see it happening. For this to be a movie with a real Christian message, I would expect to see more redemption or more of the idea that good triumphs. I don't really see that happening.
It is possible that the Lord of the Flies movie could be considered a metaphor or an allegory for Christianity. The boys run wild and do terrible things until they find a leader. This could be viewed as a metaphor because Christianity teaches that people need to find God and live by certain values in order to have a "more abundant life."
There are several scenes which demonstrate "evil" behavior. These scenes are shown with a sense of horror and these actions are addressed as wrong or immoral. The way these scenes are viewed is particularly evident in the movie.
The movie shows these scenes darkly lit and tends to play haunting music in the background. While the book also has vivid descriptions, I think the movie leans more towards an allegory of Christianity than the book does.