On it's own merits, it's pretty good.
Santa Fu on it's own is pretty good. Though unforgiving difficulty (3 lives in total and no continues), not so responsive controls (I seem to sense a small delay from pushing the button to getting the action) and glitches (at times, while fighting, my character seems to turn the opposite direction) keeps it from getting higher points.
While the stages were pretty difficult, I actually found the bosses pretty easy (except the end boss because of said glitches). And while my memory of Kung Fu is limited, it feels just like that game. If there wasn't any flashes out there with this gameplay, my score would have been higher.
Sadly, another game exists out there with a similar idea (remake Kung Fu). Kung Fu - Remix by Ironclaw2002 is just a better Kung Fu inspired game. It gave us new options so it doesn't feel like a reskin of the original, the controls are excellent in that version, and they're also forgiving in difficulty since they give you options to decrease (or increase) the difficulty. Too boot, they give you the option to continue from the level you were on. And honestly, coming into this flash, I expected it to be a reskin of that particular game.
It is a great trip down memory lane and a nice Christmas game to play around this time. But for Kung Fu fans, there is another game on this website that is better.