I felt like I missed a lot when watching this...
When I watched Legend of the Fist it seemed like a lot of background stuff that happened way before Chen Zhen got back to Shanghai had happened.
I don't think it's even a matter of watching Fist of Fury (Bruce Lee or Jackie Chan version) or even seeing the Donnie Yen TV series, it just seemed for a foreigner who knows little of the story, the film just jumps in and you have to catchup to know what's going on.
I mean I read later why Chen Zhen was spying in the Casablanca club but I'm still a bit confused on who he was doing it for? Chinese nationalist factions? Communist resistance? The film wasn't really clear. He didn't like the warlords siding with the Japanese but that didn't mean he wouldn't be sympathetic to another warlord anyways.
Anyways for a movie that was screened to foreign audiences as Donnie Yen's best in years, it really had a lot of background plot to understand (Chinese civil war history and legends of Chen Zhen) to fully grasp what the heck was going on.