The wallclip in this and the above video works when you use Sword or Hammer to attack the beam of a Waddle Doo or the sword slash of a Sword Knight at the same time you get hit. So you have to be next to the wall, and "hit" while "getting hit". I don't know if it works with other enemies, but I didn't get the clip to work with the fire enemy, in the water pool room in 1-1. So the next best opportunity was used which is the third room in 1-2. The clip is necessary in order to use "Stone" while also entering a body of water, which causes the game to glitch out - and sometimes it sends you to the credits if certain conditions in memory are met (enemy slots have something to do with it) and if you pause the game at the correct time.
NOTE SEPTEMBER 2018 === Audio at 2:09 - 3:06 has been erased in response to a copyright claim by Nintendo.
Nicovideo users: Please link all uploads back to this original. ニコニコ動画ユーザーへ：転載の際は必ずこの動画へのリンクをお願い致します。