For people who are getting black screen or their java doesnt work in google chrome/maxthon...
Use IE with latest java version which is 7u4.
If you still want to use google chrome or maxthon 3 then delete the java 7 and download version 6u32.
Use the A,W,D,S to move, J to attack ang K to jump, all the instructions are in the game.
There are also other moves:
Forward+J = stonger attack
Back+J = block
J+K = attack which deals damage to nearby enemies but when it hits them you lose HP.