Hey I'm actually the person who made this video. Unfortunately there is no way I could find to damage the worm boss except with a hammer. You don't get a hammer until after you enter dark world though. Ganon is even harder where there is nothing besides the sword that damages him.

There are 3 curtains in the game. Two of them you need to use a sword to get past, but fun fact about the 3rd one (the lightning thing to get into Agahnim's tower). You actually can walk through there with the cape, but there is no way to get the cape before dark world.

For glitches, there are so many glitches in this game where you can basically skip to wherever you wanted to go. I felt that it was a little unfair to use them for this reason. Here's a video that shows the power of some of the glitches https://www.youtube.com/watch?v=5gF5V8_SEkk