If you want to play karate flash game, then try for free Mad Karate Man. Mad Karate Man have controls pretty simple to use.
You can also check Teen Titan Karate that`s peoples favorite karate game. Lucha Wrestling is the best wrestling game i have ever player!
The object of this game is to fight with your opponent and defeat him in order to win the game. Be aggressive in your approach to attain total control over your opponent and knock him down with karate kicks and punches. Keep an eye on your health meter at the top, if it goes down you will lose the bout.