I can do this glitch semi-reliably now.
This was my current theory to walk past wall:
If you face a direction and move in that direction (call X), you move 1 pixel in direction X for each frame of the held direction. Now if you face a direction (X again) and move in a different direction (direction Y), you actually move 2 pixels in the direction Y: 1 pixel is with your body turned towards direction X, and 1 pixel is with you body towards direction Y.
Example.
I face N and walk N, i move 1 pixel N.
I face N and walk W, i move 1 pixel W while turned N, and 1 pixel W while turned W. Therefore I moved 2 pixels in the direction of W.
Therefore, if there was scenario like this:
O-open space
X-wall
N-ness
OOO
OOO
XXX
OOO
ONO
and Ness was looking in any direction except NW,N,NE, and he walked North, he would move 2 space, and the final space going onto the wall, of which he can walk down onto the other side.
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This was my current theory to step past wall...l, but it doesn't make sense when I encountered this.
http://www.megaupload.com/?d=UMHDEA97.
This is a zip file with 2 save states i them, both are in the exact same position in the valley, but state 2 moves west when L is depressed, and state 3 moves SW when L is depressed. I don't understand how a tile would be destroyed... unless your standing ontop of the tile...???
http://www.youtube.com/watch?v=6cMOKzXKGPg -- Refer to this for the videos, the 1st movement is from the 1st save state, the 2nd time is the loaded 2nd save state.