11%
11% is the lowest amount of items in which a TAS can theoretically beat the game via defeating all major bosses while using out of bounds. None of these have been fully tested, but most of the individual pieces have been tested.
Contents
Theory 1: Remove ETanks from 12%
This version of 11% performs pause abuse (chained frame-perfect pauses to survive at zero energy for as long as necessary) and memory corruption (using the X-Ray Scope at a specific position and firing at a specific angle to create artificial items and wrong warps) in order to achieve the same goal with one less percentage.
The 11% core is the following:
Mother Brain's glass would be partially destroyed such that the back of Mother Brain is exposed. It is not possible to expose the back of Mother Brain by breaking the glass from behind, as the glass can crack but will not break open from Missiles or Super Missiles fired from behind.
Samus would then climb up the right wall using X-Ray Scope, after utilizing Rinkas to become stuck, to a height that would allow her to fall from the ceiling and behind Mother Brain, similar to how the Zebetite skip with X-Ray Scope is performed.
Mother Brain's first phase is finished off with the rest of the ammo from behind. Right before doing so, Samus would need to become stuck in the wall by freezing Rinkas and sinking into them similar to how Botwoon skip works.
Mother Brain's second phase would be fought from behind her, stuck at the highest point possible behind her in the wall so that Samus can still strike Mother Brain with charge shots while not being hit by redbeam. It is not possible to pause abuse and use X-Ray Scope at the same time, so Samus would need to have at least some energy before heading to create the Varia Suit before rainbow beam.
Once Mother Brain's second phase hits zero health, Samus would climb the remaining distance to pass through the ceiling, to then use X-Ray Scope create an artificial Varia Suit in the out of bounds before Mother Brain fires her rainbow beam. Grapple Beam is required to pick up this Varia Suit, otherwise the game will crash. This Varia Suit will allow the game to be paused during rainbow beam, which means pause abuse will be allowed to continue until the point where the Super Metroid refills Samus's health, which is the reason why Energy Tanks are no longer required with this strategy.
The fight and game would finish 'normally' from that point onward.
It is not confirmed whether or not it is possible to be in a position in the room where Samus can still strike Mother Brain without taking any damage, such that she can still use X-Ray Scope to climb the remaining distance to escape the room, as again, pause abuse and X-Ray Scope cannot be used together as X-Ray Scope cannot be activated during pause fade-ins or pause fade-outs.
If Samus were to be at zero energy while out of bounds, the Varia Suit would need to be acquired during a pause fade-out, since Samus would still have zero energy the moment the suit is acquired, and it is not possible to pause during the initial moment that the suit is acquired (after the "VARIA SUIT" text box clears), until after the Varia Suit explosion animation is over. The only thing that has yet to be confirmed to confirm that this is completely possible is whether or not there is a moment where you can continue pause abusing during the suit animations caused by Varia Suit.
Interesting to note that the block which creates the Varia Suit can generate anywhere between one to four copies, and all of them can be acquired at the same time with the same Grapple extension. If this occurs and multiple copies are acquired, it can cut the animation time of the suit acquisition in half, which will allow the game to be paused earlier.
There are (currently TAS-only) 13% branches that underflow at Draygon. In particular, there is Ice-Pb, which does this with a maximum of 10 power bombs. This 11% branch would further remove Ice.
The 11% core is the following:
Doorskips, OoB movement, and L+R (specifically up Halfie Climb Room) would have to be used to navigate Maridia without any helpful items. As suitless downwards doorskip is confirmed RTA possible with the below video, one could use such doorskips to doorskip from Main Street to Crab Shaft, then from Botwoon Hallway to Botwoon's Room.
Everything else should be fairly standard.
Note this does underflow at Draygon with a maximum of 10 power bombs. The resulting sparksuit would then be used to escape.
Possible further improvements
11% may not be the minimum, and there may be other 11% options. Here, some little known TAS-only techniques are mentioned that may be able to remove items.
Morph without Morph
TAS can morph without morph, by using double- or triple-enemy knockback. On PAL, this can be done with a single spike. Here is a clip:
This should allow skipping Morph in 11% options (although possibly only on PAL). Setups would need to be found, and some parts would be particularly tricky (e.g., Phantoon's tunnel).
Destroying Mother Brain's Glass
As discoverd by sniq, TAS can fully destroy Mother Brain's glass with 5/10 ammo. It requires Ice, to manipulate Supers appropriately so they double-hit. Thus this does not really remove items, but simply replaces a Misisle or Super pack with Ice. However, if Ice were already collected (like in the first Theory option), then maybe this would allow improvement.
It cannot kill Mother Brain (this would require 6/10 ammo or 5/11 ammo). Thus, you would have to then escape Tourian to refill Supers. It has not been tested how possible this is, and what it would require. If it requires anything additional, then it may not really be notable.
