Difference between revisions of "Mother Brain Room/Low Ammo"

Revision as of 00:13, 2 February 2025

The following are notes on optimal routing of Lower Tourian including Mother Brain Room, in the absense of tools for or knowledge of Zebetite Skip, and without assuming 10 Missile Zebetite Kill.

Basics

Tourian Recharge Room allows refilling Missiles to Samus' maximum capacity available, and is the only available source of additional ammo damage in Lower Tourian. If the player lacks sufficient ammo to fight through the whole of Lower Tourian in one run, the Recharge Room must be visited one or more times.

The player's final count of Super Missiles that can be used in Lower Tourian is locked in after entering Big Boy Room, and de facto locked in after defeating Metroid Room 4, from where it is not meaningful to backtrack for more refills, if the player otherwise has sufficient ammo for dealing with Lower Tourian by any means.

Any health that is sufficient for surviving Rainbow Beam (3 tanks with Varia Suit, 6 tanks without) is also sufficient for easily damage-tanking Blue Hopper Room. The ability to defeat Blue Sidehoppers with five Super Missiles thus serves no proper gameplay purpose and should be considered a part of the game's environmental storytelling, used to demonstrate to a first-time player the scale of danger posed by the Super Metroid.

In other words, Samus' maximum capacity of Super Missiles is less meaningful than the actual count left in her possession. With care, it is regardless usually possible to bring her maximum capacity or something close to it into Lower Tourian.

Doors, Zebetites and Mother Brain's glass jar are the three obstacles in Lower Tourian standing between Samus and Mother Brain. All of these disappear permanently once destroyed, and the player can backtrack after these tasks to refill Missiles.

Basic numbers

Missiles do 100 damage, Super Missiles do 300 damage.

Early Lower Tourian

Red doors in Seaweed Room and Rinka Shaft require 5 Missiles or 1 Super Missile to unlock.

• With lowest loadouts, the former door is usually not a consideration, as the player likely also has not performed Baby Skip and must refill at least Samus' health anyway. The optimal strategy is thus to open the door with Missiles before the 1st refill.

  Taking further damage in Lower Tourian but before the Mother Brain fight is not strictly speaking required, and with 3 or 4 Reserve Tanks (+ at least one Energy Tank proper) it is technically possible to skip refilling health at Tourian Recharge Room entirely. This is unlikely to be ever practical.

• In loadouts with some lenience, using a Super Missile on red doors is often preferrable to to using Missiles, which is both faster and leaves 2 more Missiles for dealing damage.

The Gadora in Tourian Eye Door Room requires 3 Missiles or 1 Super Missile to defeat. The latter is faster and thus generally preferrable, except in very low Missile loadouts, where Super Missiles must be saved either for dealing with Zebetites effectively without excess backtracking or for getting through MB1.

No substantial threat is posed by the Gadora or in Rinka Shaft. With at least 15 Missiles, it is quite doable to unlock all three doors already before the 1st refill. However, with any loadout that leaves 5 or more Missiles of lenience with Zebetites (e.g. 25+5), the Rinka Shaft door will be optimally instead unlocked on the first Zebetite pass-thru. In any loadout with 8 or more (e.g. 30+0 or 20+5), the same holds for the Gadora.

Mother Brain room

Zebetites have 1000 health but regenerate over time, and thus killing one requires minimally any of the following ammo combinations:

11 Missiles   •   8 Missiles + 1 Super Missile   •   5 Missiles + 2 Super Missiles   •   2 Missiles + 3 Super Missiles   •   4 Super Missiles

where 2+3 is optimal in speed and damage dealt, has the least risk of mis-hitting Rinkas or bullets, and is usually preferrable whenever Super Missiles are available in sufficient numbers. 4 Super Missiles by contrast wastes 100 damage that could have been used on other Zebetites or Mother Brain.

Combining these numbers, two Zebetites can be defeated with the ammo combinations:

22+0   •   19+1   •   16+2   •   13+3   •   10+4   •   7+5   •   4+6   •   2+7   •   0+8

three Zebetites with the combinations:

33+0   •   30+1   •   27+2   •   24+3   •   21+4   •   18+5   •   15+6   •   12+7   •   9+8   •   6+9   •   4+10   •   2+11   •   0+12

and all four Zebetites with the combinations:

44+0 • 41+1 • 38+2 • 35+3 • 32+4 • 29+5 • 26+6 • 23+7 • 20+8 • 17+9 • 14+10 • 11+11 • 8+12 • 6+13 • 4+14 • 2+15 • 0+16

As the 0+4 kill wastes damage, it can only be used in the low-Missile combinations in bold; while e.g. with 4+6 ammo, defeating one Zebetite with 0+4 would only leave 4+2 ammo for the other, one Missile short. Both must be instead defeated with 2+3.

Mother Brain's glass jar requires 6 projectiles to break or 18 projectiles to completely destroy. This makes no difference between Missiles and Super Missiles. Missiles should be always used preferentially.

Mother Brain's 1st phase ("MB1") has 3000 health and does not take damage from Charge Beam. Defeating her requires minimally any of the following Missile + Super Missile combinations:

Combinations in gray do not improve on loadouts with lower Missile capacity, but they can be optimal play if, after defeating the final Zebetite, the player has at least 18 ammo left to also destroy the jar before returning for a final refill. It can be even optimal to finish destroying the jar using one or more, but at most nine Super Missiles, before returning to defeat MB1 with a refilled supply of Missiles.

Combinations in red will never come up in optimal play: using ammo to destroy the jar would call for additional Super Missiles having been available earlier, and end up using altogether more ammo than it would to merely break the jar and defeat MB1 in one go. Put otherwise: any ammo loadout between 8+10 and 0+18 would allow destroying the jar, but since 10 Super Missiles suffice to defeat MB1, the player should simply do this instead. Indeed some loadouts too low to fully destroy the jar but high in Super Missiles, such as 6+10 or 0+16, are seen to suffice also.

Later phases of Mother Brain

Mother Brain's 2nd phase has 18000 health, and in low ammo situations must be defeated primarily with Charge Beam. In its absense, she requires ammo ranging from 180 Missiles to 60 Super Missiles (the latter number only obtainable in randomizers and other mods). Combined with ammo required for MB1 gives requirements of ammo between 210+0 and 0+70 to get through the fight.

• Saved up Missiles provide higher DPS than any Charge Beam combination without Plasma Beam. (To check: also higher than plain Charge+Plasma?)
• Saved up Super Missiles provide higher DPS than any Charge Beam combination short of optimal usage of Full Beam (Charge+Ice+Wave+Plasma).
• These DPS saves will usually not justify adding additional Missile refill trips to one's Lower Tourian route, but could be possible. The best case would be in otherwise no-refill branches which begin fading to mid-range ammo loudouts. E.g. taking a refill with a 80+0 loadout allows bringing up to 50 Missiles into the fight — equivalent to 84 plain Charge Beam shots, 56 Charge+Ice shots.

Mother Brain's 3rd phase must be defeated with Hyper Beam. No ammo calculations matter by this point.

Example loadouts

40+0

30+0

Four passes through are required with the lowest sufficient no-supers loadout. Assuming you enter Lower Tourian with at least 24 Missiles on hand:

1. Refill only health on first approach. (Optional if you can brave a first pass at Mother Brain room on 1 health.)
2. Open all doors with 13 Missiles + destroy the 1st Zebetite with 11 Missiles, refill.
3. Destroy the 2nd and 3rd Zebetites with 11 Missiles each, refill.
4. Destroy the 4th Zebetite with 11 Missiles and MB1's jar with 18 Missiles, refill.
5. Defeat MB1 with 30 Missiles.

If you have less than 24 but also 5 or more Missiles on hand when first entering Lower Tourian, it will be slighly more efficient to follow this route:

1. Open Seaweed Room door, refill.
2. Open remaining doors with 8 Missiles + destroy the first two Zebetites with 11 Missiles each, refill.
3. Destroy the next two Zebetites with 11 Missiles each, refill.
4. Destroy MB1's jar with 18 Missiles, refill.
5. Defeat MB1 with 30 Missiles.

20+5

15+10

Four refills and five pass-thrus are required. All steps except the last show a few Missiles' worth of leniency.

1. Open all doors with Missiles, refill.
2. Destroy the 1st Zebetite with 11 Missiles, refill.
3. Destroy the 2nd Zebetite with 11 Missiles, refill.
4. Destroy the 3rd and 4th Zebetites with 11+0 and 2+3 ammo (in either order), refill. 7 Super Missiles remain.
5. Break open MB1's jar with 6 Missiles, followed by 9+7 ammo to defeat MB1.

10+15

Five refills and five pass-thrus are required.

1. Open Seaweed Room door with Missiles, refill.
2. Open Eye Room and Rinka Shaft doors with 8 Missiles, refill.
3. Destroy the 1st Zebetite with 8+1 ammo, refill. 14 Super Missiles remain.
4. Destroy the 2nd Zebetite with 8+1 ammo, refill. 13 Super Missiles remain.
5. Destroy the 3rd and 4th Zebetites with 8+1 and 2+3 ammo (in either order), refill. 9 Super Missiles remain.
6. Break open MB1's jar with 6 Missiles, followed by 3+9 ammo to defeat MB1.

A 10+16 loadout shortens the 2nd pass-thru (moving the Rinka Shaft door to the 3rd) and a 10+17 loadout can remove it entirely. Another 10+17 option is dealing instead with Zebetites in two 8+1 – 2+3 units.

At the cost of just slighly more backtracking, the critical no-leniency two-Zebetite pass-thru can be also moved earlier in sequence, allowing a faster reset if a shot is missed.

An option with slightly more backtracking yet but 1-2 Missiles of leniency thruout is destroying all Zebetites with 8+1 ammo, and using two Supers instead on the Eye Room and Rinka Shaft door. 10+14 and 10+13 loadouts are possible along this same track but require a sixth pass-thru for opening doors.

5+20

The most highly tedious full-packs Lower Tourian loadout, requiring a whopping six refills.

1. Open Seaweed Room door with Missiles, refill.
2. Destroy Gadora with Missiles, refill.
3. Open Rinka Shaft door with a Super Missile and destroy the first Zebetite with 5+2 ammo, refill. 17 Super Missiles remain.
4. Destroy the second Zebetite with 5+2 ammo, refill. 15 Super Missiles remain.
5. Destroy the third Zebetite with 5+2 ammo, refill. 13 Super Missiles remain.
6. Destroy the fourth Zebetites with 5+2 ammo, refill. 11 Super Missiles remain.
7. Use 5+1 ammo to break Mother Brain's Jar, followed by 10 Super Missiles to defeat MB1.

Even lower is the loadout 5+19, which requires dealing with Rinka Shaft door with Missiles, and thus one additional runback & refill.

In just higher loadouts, 5+21 removes the separate Gadora runthru, whereas 5+22 allows defeating two Zebetites (optimally, the last two) in one run with 2+3 ammo.