This only works on the original classic version (not DX or the Player's Choice version, as the warp glitch was corrected in those versions).
Just as you hit the boundary of a screen, press select to bring your map up. When you exit the map subscreen, you will find yourself the same position, but because you hit the boundary, the game will place you in that position on the next screen that you were scrolling to. You can get to all sorts of weird places and sometimes surpass previously unavailable areas.
There are different types of warping, though. Both are executed the same, but one is harder to time correctly:
- Dragging Warp: Before the map screen comes up from pressing select, you'll see the sprites on the screen drag along as if you were scrolling.
- Perfect Warp: You won't see a graphical change between the main screen and the map screen, but the warp took effect when you return to the main.
The Dragging Warp will sometimes leave sprites from previous screens on the new ones, and you're usually a few pixels from the edge of the screen as well. As such, it's easier to get stuck inside a wall by Dragging. With a Perfect Warp, you can immediately warp another screen in the same direction, even if you're stuck in a tile that normally does not allow movement.