Note that this glitch requires the use of a NES controller that allows Left and Right on the D-Pad to be pressed at the same time. By pressing Left and Right at the same time, there is a glitch in the game's programming which allows Link to move with much higher velocity than normal, so high such that he can often enter and go through walls. You can alter your speed and direction by changing your facing or tapping Left or Right on the D-Pad while the other is held.