In the opening scene of the story, two men in grey suits and black hats rescue a young man from being beaten by a gang. They take him home to his sister's house. One of the men has had his head shaved between the two scenes, although they are meant to follow on directly.
Early in the movie, Wong Tai comments about how it takes five days to get to the temple, and five days to get back home (a total of 10 days). Yet later in the movie after one of the fights, he somehow manages to get to the temple and back home in less than three days.
When the master is teaching Wong Tai about how to defend himself against the chain, he rolls up his sleeves and says for Wong Tai to attack him with the chain. Then, after they are done practising, he rolls up his sleeves again, and there appear to be forearm guards there that were not there before.