Select which attack you would like to use with the arrow keys, press space to choose it. When using the action command for jump, press the up arrow right before you hit the enemy, when using the action command for hammer, press and hold the left arrow until the red star lights up, when blocking press the down arrow right before the enemy hits you. The enemy has 30 HP, by the way.
Credits to @SonicPowerHD for the Mario vector and @TheMixerMan for the unedited Goomba vector.
