I can try. Never done reviews before, this'll probably be pretty bad.
Quick synopsis of the film: Milos, a retired Serbian porn star, finds himself and his family (he has a wife and son) low on cash. He is contacted by a former associate, who tells him that a man, Vukmir, is making the next great adult film; a true work of art. Milos reluctantly agrees to star in the film, and gets caught up in some !@#$ed up ****.
Not entirely sure how to start this review. There's no doubt: A Serbian Film is torture porn for people who think that the rape scene in Irreversible wasn't realistic enough and Hostel wasn't gory enough. If you can't stomach that sort of thing then don't bother; there aren't enough redeeming qualities in the film to make watching it worthwhile at that point.
However, if you can stomach that sort of thing, A Serbian Film may be worth watching. Milos and his brother (Marko) both end up being relatively well-developed characters, with Marko's envy of his brother turning into a remarkable plot device (after first seeming hollow and rather pointless). Milos' inner turmoil, with his struggle between his family's financial security and his morals (at least in the first half of the movie), is interesting to watch. The supporting characters in the first half of the movie seem pleasant and well-intentioned enough, but many of them turn sadistic and sinister by the end. The guy who plays Milos (some Serbian whose name I can't bother copy/pasting) is a decent actor; his lines (though poorly written [or maybe poorly translated - I don't understand Serbian, so I relied on subtitles]) are well-delivered, and it's easy to get caught up in his emotions.
The plot, while definitely lacking real depth, is engaging enough to keep you interested and doesn't want for surprises. The writers/director/whoever made good use of flashback (it's not true flashback - if you watch you'll understand - but it serves that sort of purpose) after the halfway point in the movie. There is some heavy exposition in the first half of the film, which sets the viewer up for extreme frustration and depression following the second half of the film. Unfortunately, the movie has several scenes that do nothing for plot, character development, or exposition, and leave you sitting there thinking, "why did they just show me that?"
All in all, this is a cruel, frustrating, soul-stealing movie with more than a few redeeming qualities. If you watch it, you'll probably feel awful. Masochists, this is for you.
On the other hand, it is torture porn, which drives a lot of people away. If you have a cast-iron stomach and don't mind bad dreams for a couple of days, A Serbian Film is worth a try.