If you are playing against the World 2 Boss and keep getting killed on the level, try the following trick. Walk next to the magic lamp. It will start steaming. The Boss will appear. Hit him as many times as you can before he either starts firing cannon balls or runs to the side. Then, as he is firing cannon balls, run around him in circles. He will never hit you. If you are playing with two players, have one person run around him while the other one fires at the Boss, jumping the cannon balls if any are fired at that person.