It could have been better. Tim Robbins and Bill Murray in a kid oriented movie about the last city on Earth. It could have been grand! Philosophical and funny, witted and dark. But no, they were in the film just to attract audience in roles not worth mentioning.
Also, the movie got stuck between two genres and therefore was destined not to satisfy neither audience. Logic holes in the script so blatant that it limited the viewers to the age of 8, but had social irony which could have never been understood by said kids. It was happy happy joy joy like a fairy tale, but it showed the complete obedience of a populace in the face of corrupt officials. It had a steam-punk appearance and a fine satire to the religious cultists, but a ridiculous premise.
Too bad, so much potential and so little achievement. Better luck next time. This one is merely average.