Open the game, when the help menu comes up, click on 'hide help'. You should now see an iceberg. When penguins appear on it, move the curser to the iceberg and it will become a target. Hit the penguin in the body for 5 points, get 'em in the head for... more
Move the curser to the iceberg and keep shooting in the top right corner. Eventually if you hit the right spot there will be a black dot there and the iceberg will start to sink.