OoT

GIM(Get item manipulation) explanation

So, when you exit a crawlspace, there is a brief period of time where the camera doesn't follow Link. If, during this brief period, you get the "I just got deku nuts for the first time ever" message window to pop up, then the sudden camera change will interrupt this message box, allowing enemies to move during it. If Link is hit, then he can also move during it. This delays the nuts actually being acquired until you (for some reason I don't understand) dive into water and resurface. HOWEVER, if you walk in front of various treasure chests, the item you resurface with will change, and it just so happens that the Dungeon Map chest will change this item to a Blue Potion.
Also, doing this will crash the game on both N64 and iQue. This is why Wii VC version is now used.
BenjyMLewis


Child Void Warp (Collapse skip for Any%) Explanation

The objective here is to clip out of bounds and hit a loading zone at the same frame as Link voids out, so the game loads both areas at the same time. From there you can just walk to the very end of the Collapse sequence.

To clip through this wall and hit the loading zone you need to get a really high speed backwards, and you can achieve that by doing a Hyper Extended Super Slide, or a HESS, off of one of the falling rocks.

The way a HESS works is that you use the invincibility frames from a roll to make the rock not able to hurt you, and if you hold ESS position, which is the lowest possible input the game registers on the control stick, and shield the rock on a specific frame the game sends link back at really high speed from the shield recoil, and Link keeps this speed because you are holding ESS position. The way this works is that the game developers forgot to assign a speed value to ESS position, so it just copies your last speed value, which in this case is the recoil from the shield.

Now that you are HESSing you target and untarget Zelda to get a really specific angle to clip through the wall and hit a loading zone in the back of the tower on the same frame Link voids out. Now the game loads the area of the bottom part of the tower, since that's he loading zone you hit, but since you voided on the same frame the game spawns you at the coordinates of where you entered the previous area, as if you voided out. This spawns you really far above the loaded area, and allows you to jumpslash into a half unloaded floor and walk to the last loading zone in the Collapse sequence, skipping all the other floors.

Explanation by Torje