If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Basically the idea of the game is to beat up the very nasty evil Santa, who wants to take over Christmas and stop people enjoying Christmas. There are 10 levels of evil Santas to beat your way through. They start wimpy, but they very soon become accomplished fighters. Survive for as long as you can! As for rules, there aren't any, just hit kick and beat those nasty Santas. You get more points for punching him, rather than kicking, although the crouching sweep kick, can sometimes be the only way to get out of bother.
Use arrow keys to move.
O to punch.
I to kick.