Double Dragon, also known as this week’s lonely Virtual Console game for North America, is quite different from the arcade version. At the beginning of the NES adaptation Billy can only punch and kick. Want to do the signature spinning kick? You have to level up first.
However, there is a trick to amass all of your hearts in the second level of the game. After you pass the pit by walking on top of a fence, two Williams will approach you. Wait for one of them to pass the red girders. Next, walk backwards to the other side of the pit and then walk towards the girders. The Williams appears to be gone, but you can its ghost lingers. You can continue to pummel the invisible enemy until all your hearts fill up and then move on to rescuing your girlfriend. Here’s an example of how to do the glitch.
Images courtesy of Aksys.