Both are wuxia/ about martial arts heroes set during a historical period. Both have great martial arts, great actors, great productions but plot points that are dragged on to frustrating levels that make them not worth watching imo. You might keep watching anyway if youve started them already due to their good points I mentioned and their addictive natures so its better you dont start them in the first place
Though 1 is a movie and the other a TV series, they are both filled with good martial arts action but focus more on making you laugh your way through them.
Both revolve around wandering martial artists who learn some powerful martial arts from some master and end up becoming renown. Both main characters dont rely solely on their martial arts but also on their cunning and careful planning. A Step Into the Past would be a casual recommendation for wuxia fans that have already seen all the better shows like Laughing in The Wind. Both are historicals but A Step Into the Past begins in "modern time".
Both are adaptations of Jin Young novels though they are different stories. Both are the best adaptations of their respective stories. If you liked one you'll probably like the other. First time I watched Demi Gods & Semi Devils I dropped it because from the first episode, I thought the martial arts was too over the top, exaggerated and fake/sloppy. But after giving it another go a couple months later, I realized it was pretty well done (or at least maybe in its later episodes). So I Highly recommend either for fans of wuxia series. Lots of good martial arts action.
Both are adaptations of Jin Young novels though they are different stories. Both are the best adaptations of their respective stories. If you liked one you'll probably like the other but perhaps for different reasons. I highly recommend either for fans of wuxia series