[TAS] IWBTB World 4 W/Sonic in 47 seconds (No Boss) 

Previous time: 2:21
Time saved: 1:34
New glitch I found where if you change screen in the spike hole area at the same frame as you change the gravity you get shoved into the wall. If you immediately go to the left you will run into the spike, and if you don't move your character doesn't go up. If you go to the right for a few frames you go up enough to avoid the spike, and can then go to the left and fall out of the map. However, you need to change gravity to down so that you don't fall up into the starting area after falling out of the map. This can be done at any time while you are still in the wall. If you go to the right after falling out of the map you eventually end up connecting with the boss warp (World Completion), but you need to wait a bit after a couple of screens to avoid a horizontal spike wall.
From what I can tell it makes it so you go though all of the areas but with no objects.