In the original Link’s Awakening for Game Boy, the most notorious glitch was probably the Screen Warp Glitch, which allowed you to reach otherwise unreachable locations. Sadly, this glitch was patched before Link’s Awakening DX came out.

This hack restores the Screen Warp Glitch for DX.

To use it, move Link towards the edge of a screen. Just before the screen would scroll to the next screen, press the SELECT button to bring up the map. Press SELECT again to go back, and Link should now have teleported to the opposite side of the next screen!