It was a while ago when I first saw this movie and watched it again recently. People might complain that it doesn't have enough dialogue, plot is not intricate enough, there aren't any special effects for a Sci-fi movie, and it is too low budget to be considered a good movie. But I'll say people who say such things, they don't really know how to appreciate a good movie or understand what a good movie is, because they are too used to modern day rubbish jam packed with special effects, explosions, unnecessary twists and horrible scripts.
I think everything is done just right in the movie and I especially love the way they give no sentimentality to the backdrop to the movie. No discussion of the past as to why the world they do jugging is the way it is and everyone in this world just get on with their lives in this gritty desolate world without any lamenting thoughts to the past.
I won't go into much detail, but all I'll say is just watch the movie and you'll be glad that you did. By the way, it seems like there are two versions which I didn't realise until I read the comments here and seems like the shorter version cuts out the ending. Since I thought the ending was very fitting I do recommend you watch the longer version, it just won't have the same impact without the proper ending.