Brotherhood starts by recapping episodes of the original, but no where near as well. The original stage-setting episode with Ed and Al fighting the false priest in Lior is poorly done in Brotherhood with no where near as much impact and emotion as the original. Seriously, any retreading that happens in Brotherhood can't compare to the original series.
That, however, doesn't last long. Once it goes into it's own story, anything that you know from the original series is out the window. It's completely different. What you thought you knew about alchemy has no meaning. What you thought you knew about homunculi has no meaning. Everything is completely different. And it's definitely worth every episode.
That, however, doesn't last long. Once it goes into it's own story, anything that you know from the original series is out the window. It's completely different. What you thought you knew about alchemy has no meaning. What you thought you knew about homunculi has no meaning. Everything is completely different. And it's definitely worth every episode.