Last Days in the Desert is, according to IMDb, “An imagined chapter from Jesus' forty days of fasting and praying in the desert.” Writer/director Rodrigo García surely has an overactive imagination – or not active enough, depending on how you look at it; on the one hand, Jesus speaks English with a British accent, but on the other, doesn’t he almost always?
Ewan McGregor has a dual role as “holy man” Yeshua (Jesus, for all intents and purposes) and “The Demon” (i.e., Satan). This is the most interesting aspect of an otherwise rather uninteresting film. Why does the Devil take on the appearance of Jesus? Perhaps a better question is, why has he been given it?
It’s unlikely that Satan has chosen to look like Jesus’ spitting image just to mock him – though the former certainly has a better sense of humor than the latter, who leans more toward what I’d call toilet humor were it not that toilets had not yet been invented –, considering that neither individual remarks on their resemblance.
Moreover, this Devil despises God but not Jesus – though how he can differentiate between the Father and the Son can only be explained with a massive case of cognitive dissonance. On the other hand, Jesus himself is not very well versed in his own mythology, for instance asking Satan what it’s like to be in God’s presence; he might as well ask himself, given his status as the eternal, pre-existing Logos, or second person of the holy trinity, a condition that Jesus, at least according to the gospel of John, was aware of even in his human incarnation. But, who knows? Maybe this particular Christ just happens to be non-trinitarian –, and when he tells Jesus “I'll come to you in the end. And if you give me a sign I'll help you down, and you can stay,” he sounds sincerely concerned (either that, or it’s just a reference to The Last Temptation of Christ).
All in all, I guess the whole point of this is what Matthew Modine called the “Jungian thing” in Full Metal Jacket, but taken to divine levels; in other words, that God and the Devil are nothing but two sides of the same coin, or the same side of two coins, or something; whatever it is, it’s not terribly original (in fact, it’s all very reminiscent of the Lucifer TV series, although to be fair this film was released the year prior), but at least it has some sort of point (even if it’s just a means of giving McGregor a part that has comparatively more meat in it as opposed to the thankless role of the Son of God), unlike the rest of the movie, which plays like a parable without any discernible lesson.