It rehashes the old jokes from the TV
programmes, although that isn't necessarily a bad thing. It's view of flat-caps-and-pigeons North England doesn't really exist, and never did, so the jokes have a limited shelf-life. Hence after half way it became rather ploddy.
It's also far too long. The TV
programmes had perfect length, and padding the film out makes the plot seem very slow and cumbersome.
That being said, it's a film aimed at the grown ups that loved the TV
programme, and they (not kids) will love it. No where near as good as Chicken Run, and not in the same class as Tim Burton's new film, Corpse Bride.