“Hex Tweaks” are loosely defined as sets of single-or-multiple-byte-changes that can be preformed for desirable effects. There is no clearly-defined upper limit for the number of bytes that can constitute a 'hex tweak' but they are usually less than 16 bytes' worth of changes.

These addresses are all for unheadered Super Metroid ROMs. Most of them have been tested for unwanted side-effects, but there's always a possibility of something bad popping up later that we missed. For this reason, it's highly advised that you write down each and every change that you make if you're working on a serious hack. This way you can go back and undo the changes you've made one by one until you discover that's causing a problem.

81D87 - 22 7F 96 94 to EA EA EA EA
81DAC - 22 7F 96 94 to EA EA EA EA
Disables walljump.

81DF8 - 22 F0 A8 A0 to EA EA EA EA
81E1B - 22 F0 A8 A0 to EA EA EA EA
Disables walljump, but Samus still enters the “about to walljump” pose when it is attempted.

81006 - FF 00 to 00 00
Walljump no longer forces Samus away from the wall.

8F625 - 23 to 22
Prevents Samus from losing speed by turning left/right during a spinning jump.

81F7D - 01 to ??
Speed at which Samus moves left/right through the air during a spinning jump. 
00 = very slow, 01 = standard, 02 = slightly faster, 08 = very fast, etc.

81F71 - 01 to ??
Speed at which Samus moves left/right through the air during a non-spinning jump and while falling. 
00 = very slow, 01 = standard, 02 = slightly faster, 08 = very fast, etc.

81FA1 - 01 to ??
Speed at which Samus moves left/right through the air after running off of a ledge, 
falling after doing a super jump, and de-morphing. 
00 = very slow, 01 = standard, 02 = slightly faster, 08 = very fast, etc.

82049 - 01 to ??
Speed at which Samus moves left/right through the air after performing a walljump. 
00 = slower, 01 = standard, 02 = slightly faster, etc. (found by Black_Falcon)

8267F - 20 64 8E to EA EA EA
Disables the “skid” sequence when turning left/right; allows instant stopping.

81EA2 - 1C to ??
The planet's gravity. 
Affects jump speed, jump height and fall speed whether Samus has high-jump boots equipped or not, 
except while underwater/lava/acid without Gravity suit. 
Combine with the jump-height values below for interesting effects. 
0C = lower gravity, 1C = standard gravity, 2C = higher gravity, etc.

81110 - 05 to ??
Maximum fall speed. By itself, this change isn't really noticable until Samus has fallen for awhile, 
but combined with the gravity change and jump heights, it works well for creating faster-paced gameplay.
04 = slower fall, 05 = standard, 06 = faster fall, etc. 
Anything above 07 occasionally produces small background graphical errors.

81F64 - 30 02 to ?? ??
Running acceleration and default running speed; 
30 = acceleration, 02 = max speed. 
These values are ADDED to what speed booster gives. 
Anything higher than 07 for max speed will cause errors when running at full speed with booster equipped.

81EB9 - 04 to ??
Jump/springball height. 
03 = lower, 04 = standard, 05 = higher, etc.

81EC5 - 06 to ??
Jump/springball height (with high-jump boots). 
05 = lower, 06 = standard, 07 = higher, etc.

81ED1 - 04 to ??
Walljump height. 
03 = lower, 04 = standard, 05 = higher, etc.

81EDD - 05 to ??
Walljump height (with high-jump boots). 
04 = lower, 05 = standard, 06 = higher, etc.

81EBB - 01 to ??
Jump/springball height underwater without Gravity suit. 
00 = lower, 01 = standard, 03 = higher, etc.

81EC7 - 02 to ??
Jump/springball height underwater without Gravity suit (with high-jump boots). 
01 = lower, 02 = standard, 03 = higher, etc.

81ED3 - 00 to ??
Walljump height underwater without Gravity suit. 
00 = standard, 01 = higher, 02 = even higher, etc.

81EDF - 00 to ??
Walljump height underwater without Gravity suit (with high-jump boots). 
00 = standard, 01 = higher, 02 = even higher, etc.

81EBD - 02 to ??
Jump/springball height in lava/acid without Gravity suit. 01 = lower, 02 = standard, 03 = higher, etc.

81EC9 - 03 to ??
Jump/springball height in lava/acid without Gravity suit (with high-jump boots). 
02 = lower, 03 = standard, 04 = higher, etc.

81ED5 - 02 to ??
Walljump height in lava/acid without Gravity suit. 
01 = lower, 02 = standard, 03 = higher, etc.

81EE1 - 03 to ??
Walljump height in lava/acid without Gravity suit (with high-jump boots). 
02 = lower, 03 = standard, 04 = higher, etc.

822D1 - 01 00 to ?? ??
Horizontal speed after walljump in lava/acid without gravity suit; 
speed resets to default after releasing jump button.

8209C - 04 02 to ?? ??
Underwater running speed, without gravity suit. 
04 = Samus' acceleration and slow-down rate when starting to run underwater, 
and 02 = the maximum speed she can run (found by Cardweaver).

820A9 - C0 01 to ?? ??
Speed at which Samus moves left/right underwater without gravity suit during a non-spinning jump,
and while falling. 
C0 = seems to affect jumps while standing still, 
01 = seems to affect running jumps when Samus leaves the spinning animation (found by Cardweaver).

821F9 - 01 00 to ?? ??
Speed at which Samus moves left/right in lava/acid without gravity suit during a non-spinning jump,
and while falling.

820B4 - C0 01 to ?? ??
Speed at which Samus moves left/right through the water during a spinning jump, 
without gravity suit (found by Cardweaver).

82205 - 01 00 to ?? ??
Speed at which Samus moves left/right through lava/acid during a spinning jump, without gravity suit.

820D8 - C0 01 to ?? ??
Speed at which Samus moves left/right underwater without gravity suit after running off of a ledge,
falling after doing a super jump, and de-morphing (found by Cardweaver).

82229 - 01 00 to ?? ??
Speed at which Samus moves left/right in lava/acid without gravity suit after running off of a ledge,
falling after doing a super jump, and de-morphing.

82168 - 04 01 to ?? ??
Speed at which Samus moves left/right underwater without gravity suit in ball form, 
during a springball jump. 
04 = acceleration and slow-down rate, 01 = maximum speed (found by Cardweaver).

822B8 - 04 01 to ?? ??
Speed at which Samus moves left/right in lava/acid without gravity suit in ball form,
during a springball jump. 
04 = acceleration and slow-down rate, 01 = maximum speed

820C0 - 04 02 to ?? ?? [without spring ball equipped]
8215C - 04 02 to ?? ?? [with spring ball equipped]
Speed at which Samus rolls left/right while in ball form underwater, without gravity suit.
04 = acceleration and slow-down rate, 02 = maximum roll speed (found by Cardweaver).

822A9 - 00 00 to ?? ??
Morph ball acceleration in lava/acid without gravity suit? 
Both bytes seem to do the same thing; didn't check if it was with or without spring ball.

820F0 - 04 01 to ?? ?? [without spring ball equipped]
82174 - 04 01 to ?? ?? [with spring ball equipped]
Speed at which Samus moves underwater without gravity suit after mid-air morphing. 
04 = acceleration and slow-down rate, 01 = maximum speed (found by Cardweaver).

821BC - 00 00 to ?? ??
Horizontal damage boost speed in water without gravity suit equipped.

8230D - 00 00 to ?? ??
Horizontal damage boost speed in lava/acid without gravity suit equipped.

822C9 - 00 00 to ?? ??
Adjusts how quickly Samus can turn around and begin moving in the opposite direction in ball form,
after doing a mid-air morph in acid/lava without gravity suit.

801D2 - 9C 42 0B 9C 44 0B to EA EA EA EA EA EA
Allows Samus to run in Lava or Acid (found by Mentlegen).

8D7E3 - 60 to A0
8D7E5 - 40 to C0
8D7EF - 60 to A0
8D7F1 - 40 to C0
8D7FB - 60 to A0
8D7FD - 40 to C0
Expands Samus' charge palette table to use the allotted amount of space 
(shared with the Samus death sequence). 
By default, only the first three palette lines are read, and then played backwards. 
This change increases the number of unique palette lines Samus can use when charging. 
Of the given 8 lines in smile, only 6 can be used after this change ( as apposed to the previous 3 )
(found by Mentlegen)

81EF5 - 02 to ?? [in air]
81EF7 - 00 to ?? [in water, without gravity suit]
Bomb jump and diagonal bomb jump height; also affects the jumps from power bombs. 
01 = lower, 02 = standard, 03 = higher, etc. 
For gravityless underwater bomb jumps,
01 = higher, 02 = even higher, 08 = stupidly high, etc. 
(found by Black_Falcon)

81F28 - 30 03 to ?? ??
Diagonal bomb jump X/Y or something to that effect; 
30 = vertical rise, 03 = horizontal distance/speed? 
Play around with these.

10B61 - 22 85 97 A0 to EA EA EA EA
Disables bomb jumping (found by DSO).

84023 - 20 E7 C0 to EA EA EA
Disables bomb jumping for power bombs only.

101849 - 02 to 00
Enables only diagonal bomb jumping for bombs and power bombs.

83FAC - 00 to EA
Power bombs no longer work; Samus drops a normal bomb instead, 
but power bombs can still be used for the beam-specific SBAs.

8604F - 20 1B 8F to EA EA EA
Samus no longer stops moving horizontally at the peak of a diagonal bomb jump; 
gives them an interesting 'bunny hop' effect.

8604F - 20 1B 8F to 20 DF 8E
Similiar to the change above, except diagonal bomb jumps send Samus flying a considerable distance.
Very cool.

86061 - 03 to 01
Diagonal bomb jumps move at a sharper upward angle and don't cover as much horizontal distance.

8604C - 20 DF 8E to EA EA EA
Diagonal bomb jumps no longer work; bombs and power bombs always make Samus hop straight up.

8605A - 20 E2 90 to EA EA EA
Diagonal bomb jumps move straight horizontally forever; 
player loses control of Samus and can only use bombs until hitting a wall, 
at which point Samus falls to the ground normally. 
Could be useful for hacks that involve crossing large gaps with low ceilings; 
doesn't affect normal bomb jumps.
* Changing 20 E2 90 to “20 DF 8E” instead of EA EA EA has the same effect, 
but the horizontal movement is much faster.

82648 - 9C 2C 0B to EA EA EA
Disables mockball/speedball completely. If springball is equipped, Samus bounces into the air; 
unequipped, Samus' speed resets after morph-landing.

82638 - 20 C7 92 to EA EA EA
Disables mockball/speedball in the same way as above, but with an interesting side-effect. 
Mid-air morphing behaves almost the same way as mid-air de-morping.

81F89 - 03 to ?? [without spring ball equipped]
82025 - 03 to ?? [with spring ball equipped]
Speed at which Samus rolls left/right while in ball form. 01 = slower, 03 = standard, 05 = faster, etc.

82031 - 01 to ??
Speed at which Samus moves left/right through the air in ball form during a springball jump. 
00 = very slow, 01 = standard, 02 = slightly faster, 08 = very fast, etc. 
(found by Black_Falcon)

81FB9 - 01 to ?? [without spring ball equipped]
8203D - 01 to ?? [with spring ball equipped]
Speed at which Samus moves left/right through the air in ball form after mid-air morphing. 
00 = slower, 01 = standard, 02 = slightly faster, etc.

81EB5 - 01 to ??
Bounce height when landing on the ground in ball form. 
00 = no bounce, 01 = standard bounce height, 02 = slightly higher bounce, etc. 
(found by Black_Falcon)

858E3 - 00 to ?? [left bomb]
858E5 - 01 to ?? [middle-left bomb]
858E7 - 02 to ?? [middle bomb]
858E9 - 01 to ?? [right-middle bomb]
858EB - 00 to ?? [right bomb]
Adjusts the vertical speed of the 5 bombs that Samus drops when charging a beam and entering ball form.
04 is probably the highest you'd wanna make any of them go.

858D9 - 00 81 to ?? ?? [left bomb]
858DB - 80 80 to ?? ?? [middle-left bomb]
858DD - 00 00 to ?? ?? [middle bomb]
858DF - 80 00 to ?? ?? [right-middle bomb]
858E1 - 00 01 to ?? ?? [right bomb]
Adjusts the horizontal speed of the 5 bombs that Samus drops when charging a beam and entering ball form.
These 2-byte pairs are odd, and it's not worth trying to explain how they work exactly. 
Just know that for each pair, ## ##, the left byte affects them slightly, 
while the right byte affects them heavily. 
If the bomb(s) disappear or fly down from the top of the screen,
you probably set the right byte too high. 
Play around with them on a back-up ROM to get a feel for how they work,
if that explanation didn't make sense.

858D1 - 6E 00 to ?? ?? [left bomb]
858CF - 78 00 to ?? ?? [middle-left bomb]
858D3 - 64 00 to ?? ?? [middle bomb]
858D7 - 78 00 to ?? ?? [right-middle bomb]
858D5 - 6E 00 to ?? ?? [right bomb]
Timer for each of the 5 bombs that Samus drops when charging a beam and entering ball form. 
Again, the right bytes (all 00 in this case) heavily affect how long the bombs take to explode. 
Changing 00 to 01 will add several seconds. 
Changing the left bytes (6E, 78 or 64) to 10 or lower will crash the game,
if the right byte isn't 01 or higher.

9815C - 01 to ??
Timer for how long bombs take to explode after the timer runs out (found by Black Falcon).

83860 - 3C to ??
Timer for how quickly charged shots can be fired. 
1C = more rapid charged shots, 3C = standard, 5C = longer delay between firing charged shots, etc.
(found by Flamestar666)

83A37 - 04 to ??
Number of frames that the flash from firing a charged shot lasts. 
01 = no flash at all, 08 = flash lasts twice as long, etc.

838CB - 04 to ??
Adjusts how far shots travel before their beam trail starts. 
00 = no beam trails at all, 04 = standard, 
1F = shots travel roughly halfway across the screen before their beam trail starts
(found by Flamestar666)

839C2 - 04 to ??
Adjusts how far charged shots travel before their beam trail starts. 
00 = no beam trails at all, 04 = default, 
1F = charged shots travel roughly halfway across the screen before their beam trail starts
(found by Flamestar666)

82F80 - 22 57 B6 90 to EA EA EA EA
Removes the smoke trails from missiles.

82FFE - 22 57 B6 90 to EA EA EA EA
Removes the smoke trails from super missiles.

982F7 - 22 A9 B6 90 to EA EA EA EA
Removes ALL trails; this includes charged/uncharged shots for every beam, 
missiles/super missiles, and SBAs.
* To only remove trails from specific beam combinations, see this reference.

84CC0 - AD D2 09 to EA EA EA
Disables the use of SBAs that activate when charging ice, spazer, wave or plasma 
by themselves while power bombs are selected.

84F34 - 20 to ??
Adjusts how far away the ice beam SBA circles around Samus. 
10 = smaller radius; closer to Samus, 20 = standard radius, 40 = larger radius, etc. 
(found by Flamestar666)

84F71 - 02 to 01
Allows Samus to fire beams while the ice beam SBA is in effect (found by Flamestar666).

83847 - 78 00 to ?? ??
Adjusts how long Samus' beam must be charging before SBAs activate. 
40 00 = almost instantly, 78 00 = standard; about 2 seconds, FF 01 = about 8 seconds, etc. 
(found by Black Falcon)

8D755 - 3C to 3D-77
Adjusts how long until Samus' body starts to flash while a beam is charging. 
3C = standard, 77 = about 2 seconds, 78 or higher = Samus never flashes at all. 
Any value lower than 3C will sometimes make the flash colors stick, so avoid that for now
(found by Flamestar666).

83B56 - 9D to 9E
Increases the speed of the beam charging animation (found by ProjectXVIII).

83B99 - 9D to 9E
Increases the speed of the beam charging animation even more.

83B56 - 9D to 80
Removes only the beam charging animation, but Samus still flashes and everything else works normally.

83BA2 - D0 to 80
Removes only the dots/particles from the beam charging animation.

83B90 - 9D to 9E
The large spark at the tip of Samus' gun while charging 
cycles through its animation frames slower than usual. 
Looks a lot cooler than it sounds.

83968 - 22 97 B1 90 to EA EA EA EA
Slows down the acceleration of all beams (doesn't affect missiles/super missiles).

83A32 - 22 97 B1 90 to EA EA EA EA
Slows down the acceleration of charged shots for all beams (doesn't affect missiles/super missiles).

A253C - 22 06 AE 90 to EA EA EA EA
A24D2 - 22 06 AE 90 to EA EA EA EA
Missiles and super missiles pass through walls like wave beam, 
as well as travel along certain slopes and surfaces.

82F96 - 9D to 9E
82FA0 - 9D to 9E
Missiles move very slowly through the air, almost like a torpedo. 
Doesn't affect super missiles.

98114 - 02 to 01
Swaps the projectile behavior of missiles and super missiles 
(found by Flamestar666)

98140 - 01 to ??
Timer for how long missiles, super missiles and beams take to explode 
after striking a solid surface 
(found by Black Falcon).

9826B - D0 to 80
Removes the 'flicker' effect from all beam shots. 
This makes them appear to move much more smoothly through the air, 
similiar to the GameBoy Advance games 
(found by Black Falcon).

838D4 - 00 to 10
Samus always fires charged shots (found by Black Falcon).

83857 - 4C 87 B8 to EA EA EA
Samus never fires charged shots; 
instead fires normal shots very quickly while the button is held 
(found by Flamestar666).

24F3E - 03 to ??
Alters which projectile type is needed to destroy power bomb blocks. 
01 = missile, 02 = super missile, 03 = power bomb, 04 = unused, 05 = bomb 
(found by Black Falcon).

24F77 - 02 to ??
Alters which projectile type is needed to destroy super missile blocks. 
01 = missile, 02 = super missile, 03 = power bomb, 04 = unused, 05 = bomb 
(found by Black Falcon).

824F5 - AD D0 0C to EA EA EA
Disables the pseudo screw attack, 
which happens if Samus does a spinning jump during a beam charge 
(found by Crashtour99).

84663 - 08 to 60
The end of the arm cannon no longer opens up when you select weapons on the hud
(found by SmileUser).

8178C - 89 to A9
Samus runs faster even if speed booster isn't collected or equipped. 
No sound/blue echoes/breaking speed blocks until Samus has the item equipped.

8192B - 6D 44 0B to EA EA EA
Spinning jumps no longer lose a little bit of height if run button is held with speed booster equipped.

81935 - 65 12 to EA EA
Jumps no longer gain any extra height if Samus is running with speed booster.

8E9E4 - A6 to 09
8E9EC - A7 to 0A
Samus' running speed no longer resets after landing from a jump (found by DSO).

8E9F7 - A4 to 09
8EA01 - A5 to 0A
Samus' running speed no longer resets after landing from a fall, 
such as from running off of a ledge 
(found by Rakki).

805A6 - 22 4D 91 80 to EA EA EA EA
Mutes the sound of Samus running at full speed with blue echoes.

80594 - 01 to 00
Renders the speed booster harmless. Samus only runs faster; 
no blue echoes, damage to enemies, breaking through speed blocks or super jumping. 
Running animation plays at default speed.

81797 - 01 00 to ?? ??
Delay in frames until Samus' colors change to blue during speed booster.

81796 - A9 01 00 to EA EA EA
Renders the speed booster harmless. Samus only runs faster; 
no blue echoes, damage to enemies, breaking through speed blocks or super jumping. 
Running animation plays at default speed. 
Running speed is no longer carried over to jumps, but the increased jump height remains.

80594 - 01 to D0
Renders the speed booster harmless. Samus only runs faster; 
no blue echoes, damage to enemies, breaking through speed blocks or super jumping. 
Running animation plays faster after Samus travels a short distance.

80594 - 01 to 02
Blue speed booster echoes and sound begin earlier than usual (roughly 1 screen's distance).

80594 - 01 to 04
Blue speed booster echoes and sound begin much earlier than usual (roughly a half screen's distance).

8F66F - 22 53 DE 91 to EA EA EA EA
Allows Samus to move left/right in the air during a spinning jump 
without losing the blue speed booster effect, 
and walljump if it's done on the first frames of the pose change.

81808 - AD 3C 0B to EA EA EA
Allows Samus to keep the blue speed booster effect even after the run button is released; 
running speed returns to default, and holding the run button again will increase running speed normally.

8DAD3 - 22 2F 91 80 to EA EA EA EA
Mutes the sound of Samus flashing white after running full-speed and pressing down.

8DAD8 - 3A to EA
Same as above, except the white flashing lasts forever until a super jump is used.

8F790 - B0 to EA
8F792 - B0 to EA
Disables the use of super jumps.

8054E - FF to 0F
81775 - FF to 0F
Enables the use of speed booster while in morph ball form 
by holding the run button if Samus has the spring ball equipped
(found by Flamestar666 and Kejardon).

850CE - CE to AD [vertical]
850FD - CE to AD [diagonal]
85129 - CE to AD [horizontal]
Super jumps no longer drain Samus' energy.

8514C - 0F to ?? [horizontal]
85151 - 0F to ?? [horizontal]
85230 - 0E to ?? [vertical]
85235 - 0E to ?? [vertical]
Adjusts the maximum speed of shinesparks. 
Anything higher than 0F will most likely cause graphical errors of some sort; 
note that changing both will also affect diagonal shinesparks 
(found by squishy_ichigo).

85125 - 1E 00 to ?? ?? [horizontal]
850CA - 1E 00 to ?? ?? [vertical]
Checks for Samus' energy to drop to 30 and stops the shinespark. 
Change 1E to 1F to allow Samus to continue shinesparking at 30 energy. 
Values higher than 1F raise the stopping point of shinespark energy drain; 
note that changing both will also affect diagonal shinesparks 
(found by Black Falcon).

85396 - AD C0 to 80 27
Greatly reduces the waiting time until player has control of Samus again 
after shinesparking into a solid surface 
(found by SadiztykFish).

8DAA2 - 06 to 00
Causes the speed booster palette to loop in a similar manner to when samus is charging 
(found by Mentlegen)

824BE - 8F 2D B4 09 to EA EA EA EA
Spinning jumps descend slower than usual with space jump equipped. 
Space jumping can be done by simply holding jump button. In water or lava, space jump sinks very slow;
leaving the spinning animation makes Samus fall normally.

824A0 - 10 26 to 80 0F
Space jumping in the air behaves normally. Underwater, space jumps can be done quicker and at any time, 
even after falling long distances.

82493 - F0 0F to 80 0D
Space jumps can be done quicker and at any time in air, water or lava, even after falling long distances.

82445 - AD 5E 19 to EA EA EA
Space jump works underwater/lava/acid without Gravity suit.

82493 - F0 0F to 80 0D
824C2 - F0 04 to EA EA
Space jumps remain in-place at the peak of the jump or when the jump button is released, 
can be done quicker and also by holding the jump button. 
Fire Samus' weapon or otherwise leave the spinning jump animation to fall normally.

81E97 - 80 02 to ?? ?? [air]
81E9B - 80 00 to ?? ?? [water]
Adjusts how quickly you can repeatedly use space jump. 
For air, 80 00 = more frequently, 80 02 = standard, 80 04 = less frequently, etc. 
(found by Black Falcon)
Note that the values are in reverse byte order; i.e. 80 02 is read by the game as 0280

81E99 - 00 05 to ?? ?? [air]
81E9D - 00 05 to ?? ?? [water]
Adjusts how long Samus must fall before space jump no longer works. 
00 04 = barely have to fall before you can no longer jump, 
00 05 = standard, 
00 06 = seemingly no limit to how long you can fall and still use space jump again, etc. 
(found by Black Falcon)
Note that the values are in reverse byte order; i.e. 00 05 is read by the game as 0500

112AAE - 22 12 DF 91 to EA EA EA EA
112AC7 - AD D6 09 CD D4 09 30 4F AD C2 09 CD C4 09 30 47 
to:      EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA EA
Samus' ship does not refill energy or reserve tanks.

112AB5 - 22 80 DF 91 to EA EA EA EA
112AD7 - AD C6 09 CD C8 09 30 3F to EA EA EA EA EA EA EA EA
Samus' ship does not refill missiles.

112ABC - 22 D3 DF 91 to EA EA EA EA
112ADF - AD CA 09 CD CC 09 30 37 to EA EA EA EA EA EA EA EA
Samus' ship does not refill super missiles.

112AC3 - 22 F0 DF 91 to EA EA EA EA
112AE7 - AD CE 09 CD D0 09 30 2F to EA EA EA EA EA EA EA EA
Samus' ship does not refill power bombs.
* Kudos to Rakki for making the above 4 changes work properly.

112A89 - 8D A8 0F to EA EA EA
Samus' energy and ammo begin refilling the moment she's inside the ship.

11277D - 20 84 A7 to EA EA EA
Samus' ship no longer hovers up and down, but remains perfectly still in the air.

805FF - 01 to ??
Rate that Samus' sprite flickers after taking damage from enemies, spikes, or enemy projectiles. 
00 = no flicker at all (invulnerability still remains), 02+ slower flicker, etc.

6E387 - 40 to ??
Adjusts how quickly Samus loses health in heated rooms without Varia suit. 
10 = slower, 40 = standard, 80 = faster, etc. 
(found by Black Falcon)

81E8B - 00 80 00 00 to ?? ?? ?? ??
Speed at which Samus loses health while in lava. 
00 80 00 00 = 0000.8000 (0.5 in decimal) damage per frame 
(found by Black Falcon).

81E8F - 00 80 01 00 to ?? ?? ?? ??
Speed at which Samus loses health while in acid. 
If 01 00 is changed to 00 00, acid behaves like lava. 
00 80 01 00 = 0001.8000 (1.5 in decimal) damage per frame 
(found by Black Falcon).

8023D - 6D 8F 9E to EA EA EA
80246 - 6D 91 9E to EA EA EA
Acid no longer damages Samus, but the sound effects and steam graphics remain 
(found by Black Falcon).

A0EB3 - 3C to ??
Adjusts how much damage Samus takes from touching spikes. 
2C = lower, 3C = standard, 4C = higher, etc. 
Only affects spikes with the “spike block” attribute 
(found by PJBoy).

101924 - 60 00 to ?? ?? [enemy projectiles]
102576 - 60 00 to ?? ?? [enemy contact]
Adjusts how long Samus flickers and has invincibility after taking damage,
from an enemy projectile or touching an enemy. 
60 is the number of frames in 1s, 00 is the number of frames in 100s 
(found by Daltone).

10192A - 05 00 to ?? ?? [enemy projectiles]
10257C - 05 00 to ?? ?? [enemy contact]
Timer for how long Samus is in “knockback” or the hurt pose after taking damage 
from enemy projectile or touching an enemy.

A0E9A - 3C 00 to ?? ?? [spike BTS 00]
A0ED5 - 3C 00 to ?? ?? [spike BTS 01]
A0F10 - 3C 00 to ?? ?? [spike BTS 03]
A1871 - 3C 00 to ?? ?? [air fool X-ray BTS 02]
Adjusts how long Samus flickers and has invincibility after taking damage from spike blocks,
with a certain BTS. 
3C is the number of frames in 1s, 00 is the number of frames in 100s
(found by Daltone).

A0EA0 - 0A 00 to ?? ?? [spike BTS 00]
A0EDB - 0A 00 to ?? ?? [spike BTS 01]
A0F16 - 0A 00 to ?? ?? [spike BTS 03]
A1877 - 0A 00 to ?? ?? [air fool X-ray BTS 02]
Timer for how long Samus is in “knockback” or the hurt pose after taking spike BTS damage.

86C18 - 01 to ??
Speed that Samus' sprite flickers while riding elevators. 
00 = no flickering at all, 02 = slower flickering, etc.

1195B0 - 01 to 02-08
Makes elevators move faster (going up; before room transition). 
Changing the value to anything higher than 08 causes graphical errors.

1195EC - 01 to 02-08
Makes elevators move faster (going up; after room transition). 
Changing the value to anything higher than 08 causes graphical errors.

119581 = 9C 99 07 A9 08 00 CD 98 09 D0 0A BD 7E 0F 18 69 03 00 9D 7E 0F FE 7E 0F EA
Makes elevators move faster (going down; before room transition). 
Copy this row of bytes starting exactly at offset 119581 (found by DSO).

1195D2 - 01 to 02-08
Makes elevators move faster (going down; after room transition). 
Changing the value to anything higher than 08 causes graphical errors.

119601 - 22 4D 91 80 to EA EA EA EA
After using an elevator, the humming sound continues until Samus steps off.

119558 - 22 4D 91 80 to EA EA EA EA
Mutes the humming sound of elevators going up and down.

15962 - 0C to ??
Adjusts how quickly the screen fades to/from black when going through doors. 
04 = faster, 0C = standard, 1C = slower, etc. 
(found by DSO)

23D58 - C9 00 02 F0 22 to EA EA EA EA EA
Prevents super missiles from opening red missile doors (found by JAM).

82B4E - 08 00 to ?? ??
Blinking speed of square on mini-map that Samus is currently on. 
00 = no longer blinks, 04 = blinks twice as fast, 09+ = looks kinda buggy 
(found by Flamestar666).

82AB6 - 2C to ??
82ADD - 2C to ??
82B1A - 2C to ??
Palette used by unexplored tiles on the minimap. Increments of 4.

82AC6 - 28 to ??
82AED - 28 to ??
82B2A - 28 to ??
Palette used by explored tiles on the minimap. Increments of 4.

1C5F - 10 to ??
HUD icons use different colors instead of green/super missile door colors when selected 
(found by Black Falcon).
- 20 = yellow/power bomb door color
- 08 = weird pink color
- 0C = weird blue color
- 1C = orange and yellow colors
- 04 = grey color
- 14 = no color change on select
- 18 = color varies depending on room's loaded palette

01C60 - 20 EA 9C to EA EA EA
HUD icons no longer change to green when cycling through items.

01C92 - 22 49 90 80 to EA EA EA EA
HUD icons no longer make a “click” sound when cycling through items.

84669 - F0 to 80
Alternate arm canon graphics no longer trigger when selecting missile or super missile HUD icons.

01C13 - 20 78 9D to EA EA EA
Removes the number below missiles.

01C34 - 20 98 9D to EA EA EA
Removes the number below super missiles.

01C52 - 20 98 9D to EA EA EA
Removes the number below power bombs.
* If the above 3 changes are tested in QuickMet with Samus already having the items, 
the numbers will be there, but they won't count down when missiles/super missiles/power bombs are used;
playing the game and collecting the items normally fixes this.

125BD - 80 00 10 to EA EA EA
Pressing any button will unpause the game; disables equipment screen use and map scrolling.

12FF6 - 00 to 01
Pressing right on the equipment screen while in the “beam” frame leads to “boots” instead of “misc.” 
(found by JAM).

DBDAA - 01 to 00
Disables the 'slow scrolling camera' effect when Samus is swinging back and forth with grapple beam 
(found by Flamestar666).

85DD3 - 22 D6 CA 91 to EA EA EA EA
X-ray scope no longer works when its HUD icon is selected (found by DSO).

4079A - 0A to 01
Gives the X-ray scope a much thinner “beam” than usual. 
4078A = how long the X-ray's beam takes to widen before you can move it around. 
4079A = the width of the X-ray beam itself. 
This goes up to 40, which covers the entire screen in front of Samus; 
going higher than 40 causes errors 
(found by Flamestar666).

112A7 - A9 36 00 to ?? ?? ??
Sound that's used when scrolling the pause screen map. 
See “Library 1” that's near the middle of this document for a list of sounds you can use 
(found by DSO).

11297 - 85 B1 to C6 B1
112C6 - 85 B1 to E6 B1
112D3 - 85 B3 to C6 B3
112E0 - 85 B3 to E6 B3
The pause screen map scrolls much more smoothly 
(found by DSO).

059A41 - 20 18 85 to EA EA EA
Stops the animation of the title screen between phases from loading game from emulator, 
after the 1994 up until the full title screen itself. 
It still does everything else and displays the title screen instead of the animation,
and still without the game title 'SUPER METROID'. 
But Super metroid game title still displays once it has fully loaded. 
(found by Mettyk25jigsaw)

10BAF - 22 87 86 A0 to EA EA EA EA
Removes all “screen shake” effects that activate when: 
super missiles explode, lava is rising, Kraid is emerging, Zebes is exploding, etc.

10BAF - 22 87 86 A0 to EA EA EA EA
Removes the “screen shake” effect that activates in the room after Mother Brain 
(found by squishy_ichigo).

98126 - 14 to ?? [all solid surfaces]
1021EA - 12 to ?? [every enemy except space pirates]
101CB8 - 12 to ?? [space pirates]
Type of screenshake when super missiles hit certain things. 
01 = slight up/down shake, 15 = left/right shake, 17 = angled left/right shake, 
1E = background shake left/right, 1D = background shake angled left/right, 1C = background shake up/down. 
Other values will probably have different effects, so play around with them.

9812C - 1E 00 to ?? ?? [all solid surfaces]
1021E4 - 1E 00 to ?? ?? [every enemy except space pirates]
101CB2 - 1E 00 to ?? ?? [space pirates]
Duration of screenshake when super missiles hit certain things. 
00 = no shake at all, 0E = quicker shake, 2E = longer shake, 1E 01 = VERY long shake, etc.

43059 - 00 00 01 00 02 00 03 00 04 00 05 00 06 00 05 00 04 00 03 00 02 00 01 00 00 00
Pattern for the dimming/lighting FX1 “Fireflea FX” - notice it goes from 00, to 06, back to 00. 
Modifying the values will affect how the glow behaves. 
The lower the value, the brighter the color for that frame; can be used for flickering effects.

430D6 - 06 00 to ?? ??
Timer for how quickly the “Fireflea FX” glow cycles through its dim/light phase. 
02 00 = faster glow, 0A 00 = slower glow, 06 01 = extremely slow glow, etc. 
Could possibly be used for day/night cycles.

45E11 - 80 to ??
Haze color before the main boss in an area has been killed. Must be multiple of 20.

45E16 - 20 to ??
Haze color after the main boss in an area has been killed. Must be multiple of 20.

45E54 - 0F to ??
Adjusts how far the “haze” FX1 extends from the bottom of the screen, as well as transparency? 
00 = entire screen is covered with transparent haze color, 0F = standard, 
1A = slightly noticable haze along the lower portion of the screen, etc. 
(found by Black Falcon)

59C98 - 88 to 93
Removes the greenish haze from the title screen (found by DChronos).

924D - 88 to 93
Removes the greenish haze from the game over screen (found by DChronos).

15490F - 22 to 6B
Removes the gray haze from the bomb Torizo's room, and allows you to use any other FX1 in place of it.
Easiest way to do this is to use another Crateria room's FX1 pointer after you change 22 to 6B 
(found by Sadiztyk Fish).

80264 - 04 to 05
80269 - FF to 0F
Changes the graphic animation when Samus touches the surface of acid from steam(?) to bubbles 
(found by Black Falcon).

Found by JAM.

40B5F - 22 A2 D5 90 to EA EA EA EA
Disables the use of Crystal Flash.

855C9 - 33 00 to ?? ??
Crystal Flash can be activated when Samus has less energy than this value.

855D0 - D0 18 to EA EA
Disable reserve energy checking. Allows Samus to use Crystal Flash even with full reserve tanks.

855D6 - 0A to ??
Number of Missiles Samus must have to start Crystal Flash.
8564C - 0A to ??
Number of Missiles consumed during Crystal Flash.
856EF - 32 to ??
Amount of health added per missile consumed during Crystal Flash.

855DE - 0A to ??
Number of Super Missiles Samus must have to start Crystal Flash.
856FD - 0A to ??
Number of Super Missiles consumed during Crystal Flash.
85712 - 32 to ??
Amount of health added per super missile consumed during Crystal Flash.

855E6 - 0A to ??
Number of Power Bombs Samus must have to start Crystal Flash, 
after the initial one to trigger the move has been detonated.
85720 - 0A to ??
Number of Power Bombs consumed during the Crystal Flash.
85735 - 32 to ??
Amount of health added per power bomb consumed during Crystal Flash.

6E37D - 21 to 01
Removes Gravity suit's protection against heated rooms, 
meaning that Gravity suit can be collected first without making Varia useless 
(found by Jathys).

20717 - 22 21 87 84 to 22 BA DE 91
Varia suit and Gravity suit behave like regular items when collected 
(bypasses the sound, flash, and moving Samus to the center of the screen).
Updated to also refresh Samus' palette, 
change these bytes to EA EA EA EA instead of 22 BA DE 91 for the original tweak.

2096C - 79 00 00 to EA EA EA
Energy tanks no longer add +1 energy tank, but instead just refill energy. 
Useful if you start Samus out with a higher number of energy tanks.

1410E9 - 04 00 to ?? ??
Changes which item will cause the blue “EYE” enemy to shine its yellow light at Samus. 
04 00 = morph ball 
(found by JAM).

1410E6 - A4 to ??
Changes which type of item will cause the blue “EYE” enemy to shine its yellow light at Samus. 
Changing A4 to A8 makes it activate from beams, meaning the 04 00 would become Spazer 
(found by JAM).

25193 - 00 02 to ?? ??
Changes which item is needed to activate the lower Norfair Chozo statue 
(the one that lowers the room's acid). 
00 02 = space jump (default), 04 00 = morph ball, etc. 
(found by JAM)

16EDA - 1E to 1F
When starting a brand new save file (“no data”), 
Samus immediately begins at the Crateria landing site after “start game” is selected, 
instead of displaying the area and map screens. 
For this to work, the “hide intro” box must be UNchecked in SMILE 
(found by Black Falcon).

2533B - AD A4 09 to ?? ?? ??
Crumbling Chozo statue check for equipped items. 
Could be changed to beams, or health, or whatever 
(found by DSO).

2533E - 29 00 10 to ?? ?? ??
Crumbling Chozo statue check for bombs in equipped items. Change to whatever item you want 
(found by DSO).

58674 - A9 38 85 74 A9 58 to A9 20 85 74 A9 40
Stops the blue palette swaps during the zoomed-in title intro. 
Only useful if you're changing the title screen's colors.

5A25B - 
A9 23 00 22 4D 91 80 60 A9 26 00 22 4D 91 80 60 A9 27 00 22 4D 91 80 60
to
60 FF FF FF FF FF FF FF 60 FF FF FF FF FF FF FF 60 FF FF FF FF FF FF FF
Silences the baby metroid sounds on the title screen. 
(Found by Moehr).

2846 - 02 00 to ?? ?? [left]
27D7 - 02 00 to ?? ?? [right]
25F4 - 02 00 to ?? ?? [up]
2593 - 02 00 to ?? ?? [down]
Camera scrolling speed while panning away red scroll blocks.

5E00E - 03 to ??
5E1E4 - 03 to ??
5E27A - 03 to ??
5E2E8 - 03 to ??
5E329 - 03 to ??
5E370 - 03 to ??
If player have ending time in hours lower than this value, show the best ending. 
(Found by JAM)

5E1E9 - 0A to ??
5E2ED - 0A to ??
5E375 - 0A to ??
5F559 - 0A to ??
5F59B - 0A to ??
5F5BE - 0A to ??
If player have ending time in hours greater than or equal to this value, show the worst ending. 
(Found by JAM)

5E00B - E0 to DE
5E1E1 - E0 to DE
5E277 - E0 to DE
5E2E5 - E0 to DE
5E326 - E0 to DE
5E36D - E0 to DE
5F3D6 - E0 to DE
5F556 - E0 to DE
5F598 - E0 to DE
5F5BB - E0 to DE
Change checking for hours to checking for minutes when showing ending. Should be useful for mini-hacks. 
(Found by JAM)

5A592 - A9 A7 A5 to A9 2F B7
Skip intro text when starting a new game - starts at the 'Fly to Ceres' cutscene.

33951 - A9 8E 00 to A9 ?? ??
3395A - A9 55 00 to A9 ?? ??
X and Y coordinates of the Ridley statue.

33961 - A9 84 00 to A9 ?? ??
3396D - A9 88 00 to A9 ?? ??
X and Y coordinates of the Phantoon statue.

14667B - 0D to 09
Fixes WS sparks setting themselves invisible if the area main boss isn't dead.

278413 - CD to 6F
Mutes all music in the game. (Found by Zeke)

36CA3 - 40 00 to ?? ??
Enemy respawn timer.

1024AF - A0 F4 01 to A0 ?? ??
Speedboost damage value. Mind your endianness! (F4 01 = $01F4).

1024BA - A0 2C 01 to A0 ?? ??
Shinespark damage value. Mind your endianness! (2C 01 = $012C).

1024C2 - A0 D0 07 to A0 ?? ??
Screw attack damage value. Mind your endianness! (D0 07 = $07D0).

1024CC - A0 C8 00 to A0 ?? ??
Psuedo screw attack damage value. Mind your endianness! (C8 00 = $00C8).

144B81 - F0 49 to EA EA
Walking version of Robo enemy is always on. 
Now you can edit your info files in RF too so that the question in the box is answered. 
(Found by Moehr)

123A46 - F0 0B to F0 E9
Crocomire invulnerable to missiles
123A4E - F0 03 to F0 E1
Crocomire invulnerable to supers