secret worlds: hillside vista
After entering the room, look at the wall ahead and you'll notice some cracks. You can jump through the part with a single vertical crack (just above the branch). If you're not sure where it is, the video starts out looking at it. When ready, get a running start and jump off the edge, using your next jump about a second later. There's some timing involved; you'll hit your head on the solid part of the wall if the second jump is used too early.
When you go through the wall, immediately turn right (while still holding forward) and you should stick to it. Morph and place a bomb, moving forward and slightly to the left during the ascent. Unmorph at the peak and you should land on a ledge. The landing will either be a normal or "botched" one. For a normal landing, just follow the video and space jump past the end of the ledge, where it sticks out. You'll land on air and enter the secret world.
Botched landings are much more likely to happen. You won't be able to jump or move normally, and standing still causes you to "bounce" on the ledge. During each bounce, you can move on the way down but only have a moment to do so. Wait until you suddenly pop into the air, then immediately move the stick and let go as you hit the ground. If you repeat this, you may find a spot that cancels the bouncing and allows you to space jump, but be ready to fall off the ledge if it doesn't happen soon. Falling will take you back inside the room so you can start over.