Screen Warping does not exist in the DX version of the game and is only present in some revisions of the original black and white version (i.e. v1.0 and v1.2). If one presses the SELECT button to bring up the map just as Link crosses a screen boundary, he will warp to the next screen while retaining the same position he had on the previous screen. This breaks the game wide open and can be used to beat it in less than 4 minutes. Link can also get stuck in walls or enter glitched versions of the game's underworld maps by using the screen warp glitch.