The best bits all centre around the evil guys. Their visual representation is really creepy, original and different, with their monitor style faces showing the most evil, smug grins as they slink around, snickering in suitably menacing fashion. The fight scenes are also reasonably effective in a Vauxhall Conference version of Crouching Tiger, Hidden Dragon kind of way. The special effects overall are average, but considering the budget they hold their own against bigger blockbusters than this, and wouldn't look out of place in Torchwood. I'm not sure if that is praise or criticism.
Maybe these criticisms are a little harsh but the combination of issues make it impossible to concentrate on the story. A story which is arguably one of the film's strong points. Pound for pound it's probably one of the best films ever made but unfortunately it doesn't quite cut it in the Premier League of film. Worth a watch though, and if your expectations are not too high it's relatively enjoyable.
If you like this you could try:
Dark City, Labyrinth.