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G-mode (Grey mode or God mode) is one of the three X-Ray Scope glitched modes, the other two being X-Mode and R-Mode. It is possibly the most powerful with the weirdest effects.

G-mode requires X-Ray Scope and at least one Reserve Tank.

For speedrun purposes, G-mode is mostly a time save for low% categories. It is used in all optimal routes of 14% categories that collect X-Ray: 14% xIce, 14% xChargeless, 14% xSpeed, and 14% xAmmo. It would additionally be used in the theoretical 14% xPb.

In addition to simply being a faster method, it can be helpful in 14% categories to avoid the use of L+R. G-mode is required to avoid L+R wall jumping in 14% xChargeless, a theoretical PAL-only route of 14% xSpeed, and the theoretical 14% xPb. Note L+R wall jumping cannot be avoided in 14% xAmmo.

G-mode would also be helpful in low% version of other categories. It is used multiple times in the current low% RBO run. In low% Map Completion, this would allow collecting Speed-locked map squares without Speed Booster, a flash suit, or a blue suit.

The reason why G-mode isn't useful in more categories is because of the time needed to set it up. For example, the current 100% TAS uses G-mode to enter Maridia (much faster than the RTA method).

Given its strength, G-mode is very powerful in puzzles, challenges, hacks, and randomizers (or more commonly "plandos"). Since it is so strong, a discussion of all of its applications would be way too long. Therefore, after a somewhat thorough discussion of entry conditions and limitations, this article has three main sections.

The first, Major Speedrun Uses, discusses the major uses of G-mode in speedrun categories. This section is all that needs to be understood in order to use G-mode in any of the current routes of categories for vanilla Super Metroid.

The next section, Unusual Uses, gives some broader principles with use examples. This section would be good to review if one is trying to develop new G-mode strategies, or is attemping G-mode applications to a hack, randomizer, or puzzle.

The final section, Non-Examples, gives some situations where G-mode does not work and explains why.

Entering G-Mode

Entering G-mode is basically a more precise version of entering R-mode, so most of this description holds. To keep information on G-mode centralized, this will be repeated below.

G-mode is activated by entering a transition, having Samus' Energy deplete to 0 during the transition, using X-Ray on the first frame after the transition while Reserves automatically trigger, and releasing X-Ray in a specific frame window around when Reserves finish filling. This leads to the following steps:

1) Have Reserves set to automatic, X-Ray selected, an enemy positioned so it will hit Samus during the transition, and a small enough amount of Energy such that the enemy will damage Samus down to 0 Energy.

2) Enter the transition while in a pose that X-Ray can be used.

3) Be hit by the enemy during the transition.

4) Hold dash during the transition, so X-Ray is used on the first frame.

5) Continue to hold dash while Reserves fill.

6) Release dash in a small frame window when Reserves are about to finish filling.

The only difference from R-mode is this last step.

If dash is released very early, nothing notable will happen. If dash is released late, then instead R-mode will be activated. If successful, the door will not close behind Samus (if at a transition where there is not a door, see Effects to figure out how to determine it was successful in other cases).

Based off the above description, it is fastest to enter G-mode with a very small amount of Energy in Reserves. For most applications, it is usually optimal to have 4 Energy in Reserves. See the below sections for a discussion on this.

The Frame Window

The frame window is dependent on the amount of Energy in Reserves.

  • If the amount of Energy in Reserves is less than 5, then the frame window is equal to the amount of Energy in Reserves.
  • If the amount of Energy in Reserves is between 5 and 11, then the frame window is equal to the amount of Energy in Reserves plus 3.
  • If the amount of Energy in Reserves is greater than 11, then the frame window is equal to 3.

Where the frame window is also depends upon the amount of Energy in Reserves.

  • If the amount of Energy in Reserves is less than 12, then the frame window is as soon as you have control over Samus after the transition. Thus, if X-Ray is released too early, it will simply never be used.
  • If the amount of Energy in Reserves is greater than 11, then the frame window is the last 3 frames of health entering Samus' Energy Tanks. If we let n be the amount of health entering her tanks (so n is the minimum of Energy in Reserves, and the total of 99 + 100 * # of Energy Tanks), then the first frame where dash can be no longer held is when Samus' Energy is n-2, n-1, or the first frame when her Energy is n.

Note dependent on input lag, when X-Ray must be released could appear to be different. Visually, for entering G-mode when Energy in Reserves exceeds 11, the X-Ray Scope re-widens after the Reserves have finished deploying. The three frame window is immediately before this happens.

From this discussion, it sounds like an optimal amount of Energy in Reserves is 11, where the frame window is at a maximum of 14 frames. However, due to the next section on G-mode immobile, most applications of G-mode have 4 Energy in Reserves (with a 4 frame window) and the remaining applications have full Energy in Reserves (with a 3 frame window).

G-mode Immobile

When G-mode is activated, Samus will be unable to move until knockback frames...knock her back.

Since knockback from an enemy lasts 5 frames, if Energy in Reserves is less than 5 then this happens automatically.

If Energy in Reserves is at least 5, though, then Samus will be unable to move until an enemy hits her (or G-mode is canceled by using X-Ray). Thus, one must wait around until an enemy hits Samus.

Therefore, in cases where it is possible to perform the needed actions at 4 Energy, it is optimal to have only 4 Energy in Reserves: This way, Samus may move immediately, and the frame window is maximized.

In any other case, the actions require having a larger amount of health. Thus, usually a full health G-mode would be performed instead. Then one must wait for a (usually global) enemy to hit Samus.

The maximized frame window at 11 Energy in Reserves is more of a curiosity. If this is used, then it is the worst case: Samus has very low Energy, and she cannot move until she gets hit by an enemy.

When getting knocked out of G-mode immobile, do not hold forwards. This will cause a downwards knockback which may immediately ground Samus and she may still be immobile. This applies to both the low health version (with the automatic knockback), and when waiting for an enemy.


Most of the effects of G-mode can be summarized as PLMs (Post Load Modifications) not behaving properly. They will fail to update: The game is sort of acting like X-Ray is constantly in use.

Some examples:

  • The door behind Samus upon entering G-mode will not close;
  • Doors and gates cannot be opened;
  • Scroll PLMs will not work, which leads to graphical glitches (like the screen not following Samus);
  • Bombs and power bombs will not break blocks;
  • Shot blocks and super blocks cannot be broken;
  • Crumble blocks will not crumble;
  • Treadmills will not push Samus;
  • Sand will only effect Samus for a very short time (less than a second);
  • Grapple can only interact with grapple blocks for a very short time (less than a second) and will then simply shoot through grapple blocks (they are still solid to Samus);
  • Items cannot be collected (and act like air);
  • Drops from enemies will not spawn;
  • Projectiles from enemies will not be visible, and will not move (they can still damage Samus);
  • Heat will not damage Samus (other environmental damage, like lava and acid, will).

Additionally, if too many PLMs are interacted with, this overloads PLMs and the behavior of blocks will return to some "default" state. This is the same behavior that makes Reverse Frog Speedway work. This default state is:

  • Shot, Super, and Power Bomb blocks act solid;
  • Crumble, Bomb, and Speed blocks act like air (one qualm: If a Bomb block is (power) bombed or if a Crumble block is stepped on before PLMs are overloaded, then it will instead act solid).

This notably allows passing through Crumble blocks from below, and allows passing through Speed blocks without Speed Booster, a flash suit, or a blue suit.

Overloading PLMs can be done by interacting with enough PLMs, possibly the same one multiple times. Some example methods:

  • Passing through a Scroll PLM (frequently found in secret paths or tunnels);
  • Passing through an item;
  • Entering sand;
  • Grappling a grapple block until grapple stops interacting with it;
  • Destroying bomb blocks with Screw Attack, a shinespark, or a blue suit;
  • Bombing blocks such that normally bombing them would reveal what type of block it is (One note: Bombing a Crumble block that has been stepped on will not work);
  • Stepping on enough different Crumble blocks.

Other than these basic effects, there are effects that depend upon which room Samus is in.

Direct G-mode

Direct G-mode is before any transition tiles are interacted with in G-mode.

Direct G-mode is a particular example of R-mode, so will have the same effects. This includes graphical glitches, forced stand, and the power bomb effects. The graphical glitches may look different.

A note about G-mode forced stand: Since drops do not spawn, this requires a Crystal Flash.

Direct G-mode will be canceled when entering a transition tile, just like R-mode is lost when entering a new room. It will become:

Indirect G-mode

This is the state of G-mode after triggering a transition tile. Note since the door does not close behind Samus when initially entering G-mode, this room can usually be entered. Also, after entering this room, the door will now close behind Samus (or more accurately be instantly closed).

Other transitions also work, like elevators or sand pits.

In indirect G-mode, the screen will return to the normal dimness level. Door shell colors will not appear but they are there: it is purely graphical. The pause screen will look normal again.

The most important effect of indirect G-mode is that wave and super gates will not spawn. Therefore, these gates can be passed and G-mode can be canceled on the other side, to allow crossing them without opening. In particular, this allows getting past gates that face the wrong direction.


G-mode is canceled when Reserves automatically trigger (when in direct G-mode) or X-Ray is used.

The most evident limitation is the enemy positioning needed to enter G-mode. Note that the damage taken must be from an enemy. Projectiles will not work (they do not move during transitions, so will always damage Samus before the transition is triggered). Additionally environmental damage (e.g., heat) will not work. Dependent on if one want direct or indirect G-mode, this set-up either has to exist in the desired room or in a neighboring room (dependent upon if transitions in the desired room have doors).

Another limitation is that G-mode requires using X-Ray, so activation will cancel a shinespark suit. G-mode can be activated with a blue suit, although requires a 1 frame movement (i.e., Samus must be one pixel away from the transition tile).

G-mode requires triggering a transition while in a pose that X-Ray can be used. This isn't a problem for horizontal transitions, where Samus can simply walk into the transition. For vertical transitions, this an issue. Upward transitions can be handled similarly to R-mode.

Downward transitions are also similar to R-mode, and are hence incredibly problematic. See below for an example. The current 100% TAS does this, which is discussed in Entering Maridia from the top.

The most important limitation of G-mode is that doors cannot be opened, and shot, super, and power bomb blocks always act solid. Therefore, mobility with G-mode is difficult.

Major Speedrun Uses

Here, all major use cases of G-mode in speedrun categories is given. This includes esoteric categories, like low% RBO and RBO glitched.

Reverse Lower Norfair Entry

In G-mode, when PLMs are overloaded, Crumble blocks act like air. This allows entering Lower Norfair by going through the Crumble blocks in Single Chamber. This is frequently faster (and possibly easier) than going through Lava Dive Room and Worst Room In The Game, especially in 14% categories.

The standard method for this G-modes towards Bubble Mountain with 4 Energy in Reserves, uses a scroll PLM to overload the PLMs, and then cancels G-mode next to the door. If neither Varia or Gravity is collected (like in low% RBO), a Crystal Flash must be used with this method (before canceling G-mode). Here is an example use:

This method, especially if done without a Crystal Flash, has the issue of dealing with the Three Musketeers.

There are two modifications to this method. One is to G-mode with a blue suit, and use the blue suit to kill the Three Musketeers. Two is to use a full health G-mode, to avoid the need to Crystal Flash without Varia or Gravity. This second point probably requires at least 2+3 Energy+Reserve Tanks to survive the hellrun. Here is an example that does both of these modifications:

If you want to do this without breaking the graphics, you should walljump outside of the morph tunnel a couple of times. This overloads the PLMs before entering the tunnel.

Entering Maridia from the top

In Red Tower Elevator Room, one can cross the green gate into Red Fish Room by using indirect G-mode. This is used in any 14% category with X-Ray, to avoid having to climb Main Street. This has two main methods.

The first is to use a Zero to G-mode into the Save Room, and then double back to Red Tower Elevator Room. This method is slower, but does not break the graphics.

The second method is to use a Sidehopper in Beta Power Bomb Room or a Zebbo in Hellway to get direct G-mode in Red Tower Elevator Room. Then, ride the elevator up and back down to get indirect G-mode.

The current 100% TAS takes a third option of G-moding downward in Crateria Kihunter Room. This is most likely not RTA viable.

Some category applications, like 14% xSpeed or 14% xChargeless, should perform this entry with a blue suit and then use the blue suit to spark to the top of Mt. Everest. Using X-Mode in Hellway would be the fastest method from the Save Room with Speed Booster, and is hence probably what should be used in category runs. This is done in this example, which also shows the Hellway G-mode method.

As a final useless note, it is possible to enter Maridia without Morph by using G-mode Morph. This requires an indirect G-mode morph into the elevator room, some item to get boosted up to the hole, and then using the bugs to refill and doing another G-mode morph. This is pointless, outside of puzzles or plandos.

Crossing Botwoon Energy Tank Room

Botwoon Energy Tank Room requires an ability to jump up to the passage (if one does not have a way past the speed blocks). This can be done with L+R wall jumping, but without this cannot be done with no equipment. Also, avoiding the Energy Tank when going from left to right can be difficult suitless.

G-mode can be used to pass through the blocks and sand. Entering the sand will instantly overload PLMs, and cause the sand and Speed blocks to act like air. This can be done in either direction. Left to right, a Puyo may be used:

Right to left, a Zoa may be used:

G-mode Ridley

In low% RBO, Ridley is quite problematic. The current low% RBO run uses G-mode to handle Ridley.

The benefit of this is that there is no heat damage. This is taken further: A Crystal Flash is performed, and then another power bomb is placed. This causes Ridley to permanently run away from this power bomb. Note after this is done, no further power bombs may be placed and X-Ray will not work.

To end the fight, G-mode must be canceled. This must be done by automatically triggering Reserves. Jumping on top of Ridley in a particular location will cause this to happen, and allow Ridley to immediately grab Samus. All of the particulars of the set-ups can be found in the low% RBO run linked above.

Theoretically, this can be done without the need to Crystal Flash. This requires a very low health fight (a full health G-mode with one hit from Ridley is maximum health possible). Additionally, all flames produced by Ridley will be invisible and stay wherever they spawned. Thus as the fight progesses, jumping becomes more and more dangerous. Additionally, having enough time to be able to collect Ridley's drops may require a number of tanks. This is far from viable in runs, but is possible.

As a final note, the R-mode Ridley method will also work, since direct G-mode is also R-mode. Both methods may not be done simultaneously.

G-Mode Save Station

G-Mode can also be used to cause save stations to execute a different PLM than normal, including giving Samus items. Once Samus steps onto the Save Station, it starts cycling through through the available PLMs. Once G-Mode is disabled by activating X-Ray again, it executes the currently-selected PLM.

The current major use is RBO Glitched. The current route uses this to collect Gravity Suit before Ridley, by disabling G-Mode on a specific frame after landing on the save station.

TODO: Get a more detailed description of this specific method. Also get a more detailed description of what is possible in general.

Unusual Uses

Here, some general principles for G-mode applications are given with an example use.

First, note that the above examples already show passing through Crumble blocks and crossing gates.

G-mode Morph

Also called "morph without morph". G-mode allows morphing without the Morphing Ball. This is only useful in puzzles, randomizers, or potentially hacks that for some reason don't give Morph for a long time.

This is done by pressing backwards during the knockback that initially knocks Samus out of G-mode immobile. The backwards press must be during the knockback frames, so is a five frame window. If done way too early, Samus will turn around and then be hit; if done slightly too early, Samus will turn-around kago the hit; if done too late, Samus will turn around after the knockback frames.

If the fast G-mode method is done, with less than 5 Energy in Reserves, then the frame window for entering G-mode interacts with the frame window for pressing backwards. With n health in reserves, the number of frames that backwards can be pressed is 8-n. There must also be a short pause between X-Ray release and pressing backwards. The frame window for pushing backwards is always in the same spot (no matter when X-Ray is released), and is always 1 frame after the last frame that X-Ray can be released (if backwards is pressed during this 1 frame instead, then Samus turn-around kagos the knockback). In other words, the following are the valid input patterns after the transition (with D meaning dash must be pressed, d meaning dash may be pressed, < meaning backwards must be pressed on one of these frames, and _ meaning an empty frame):

  • 4 Energy in Reserves: Dddd_<<<<
  • 3 Energy in Reserves: Ddd_<<<<<
  • 2 Energy in Reserves: Dd_<<<<<<
  • 1 Energy in Reserves: D_<<<<<<<

The variable number of frames that one must wait dependent on X-Ray release can make this obnoxious for timing purposes. If used to entering G-mode, usually 2 Energy feels the easiest, where the window for pressing backwards (6 frames) is much longer than the waiting period (1 or 2 frames).

This is a one time Morph: As soon as Samus unmorphs, the trick would have to be done again to be able to Morph. While in this morphed state, Bombs, Power Bombs, and Spring Ball may be used. It is still G-mode, so in order to break Power Bomb blocks one must lay a power bomb, unmorph, and then cancel G-mode.

With this technique, without going Out of Bounds, and in the usual Super Metroid layout, 62 items may be collected RTA without Morph. An additional 13 may be collected with immediately softlocking if the item is not Morph.

An example use case, getting down to Bomb Torizo without Morph using G-mode immobile:

And getting to the same location using the low Energy method with different items:

Remote Acquiry

In G-mode, items behave as air and are PLMs so may be used to overload PLMs.

If an item is passed through before PLMs are overloaded, and then G-mode is canceled, the item is collected. This allows collecting items from very far away. Note this must be done in direct G-mode.

This becomes even more powerful when combined with G-mode Morph above, allowing the collection of Morph-locked items without getting softlocked. Here is an example collecting Beta Missiles using Spring Ball:

Passing through Speed Blocks

One example of this was given above, passing through Botwoon Energy Tank Room.

This may additionally be used wherever else there are Speed blocks. In particular, X-Ray and a Reserve Tank may access all Speed-locked map tiles in Map Completion]. This will be much slower, but opens up other possibilities in low% consideration.

One more frequently done example is G-moding to access the Aqueduct items. This requires either Bombs or Grapple, to overload PLMs. It is also an alternative to the much harder suitless right side X-Ray Climb. Here is an example:

(Very) Deep Stuck X-Ray Climbing

Since the door does not close behind Samus when G-mode is initially entered, she may walk very deep into the door and cancel G-mode. The door closes on Samus while she is in standing position, so she may X-Ray Climb from here.

This allows getting very deep in doors. Thus, it allows x-ray climbing past door shells lying above this door. Here is an example, x-ray climbing past the top right green door shell in Bubble Mountain:

X-Ray Climbing from Strange Positions

When PLMs are overloaded in G-mode, various blocks act as air. However, they are still there. If G-mode is canceled while Samus is standing in these blocks, then she may begin to X-Ray Climb.

If done in conjunction with a G-mode forced stand, this can allow X-Ray climbing from very strange positions. Here is one example in Big Pink:

Crossing Sandy Rooms

Sand is a PLM, so will not effect Samus in G-mode. This allows crossing sandy rooms with fewer items. Here is an example, that crosses East Sand Hall with only X-Ray and a Reserve Tank:

This example is also notable as an RTA viable downward G-mode.


Here, some examples that do not work, with a description of why, are given. Non-examples should always be studied if attempting to learn.

Only a couple of examples are given, specifically chosen as ideas that have been asked about before.

GT Missiles

The idea is to use G-mode to pass through the crumble blocks to collect GT Missiles without Space Jump.

This does not work, because there is no way to G-mode into GT's room from the bottom right (and GT falls too late to be able to G-mode out of the room and then get indirect G-mode in the room).

It is possible to G-mode from the top left. By using the Missiles to overload the PLMs, the crumble blocks can be pass through. However, the Supers for two reasons:

1) PLMs have been overloaded, so items cannot be collected without canceling G-mode;

2) The supers are hidden by a shot block, which cannot be broken without canceling G-mode.

Note the Supers may be collected without killing GT by performing an R-mode clip past the crumbles.

Cathedral Missiles

The idea is to use G-mode Morph to collect Cathedral Missiles without Morph.

This does not work because the item is hidden by a shot block, which can never be broken in G-mode.

Waterway Energy Tank

The idea is to use G-mode to pass the Speed blocks to collect Waterway Energy Tank.

This actually does work: Use a Zero to get indirect G-mode in the room. Then use Bombs on the Speed blocks until they act like air.

However, G-mode must be canceled in order to collect the item, since PLMs have been overloaded to pass the Speed blocks. Once G-mode is canceled, Samus is locked in the tiny area back here. This could potentially be useful if the only goal is the collect the map square (like in Map Completion), if it is a puzzle that ends upon collection of this Energy Tank, or in a multiworld where this item belongs to somebody else.

As a major glitch note, it is possible to do 1-frame G-mode steps into the Speed blocks and X-Ray Climb to Out of Bounds. From there, escape might be possible. Note that there are also major glitch methods to collect this item without power bombs, which would avoid the need for G-mode as well.

Going up the back of Gauntlet

The idea is to G-mode into Green Pirates Shaft and then go up to the back of Gauntlet.

The issue is that there are shot blocks. Shot blocks always act as solid in G-mode.

Wrecked Ship Reserve

The idea is to G-mode to access the Wrecked Ship Reserve Tank.

The issue is there is no way to G-mode into the bottom of this room: No enemy allows this to happen. There are Workrobots, but they only damage Samus via projectiles which will not work to activate G-mode.

It is possible to G-mode into the top of this room by using a Zeb, but this does not help.

Old Description

This is maintained for historical reasons.

From the text at TASVideos:

Discovered by EternisedDragon in 2015. Running out of energy during a door transition does not trigger the R-Tank's "Auto" feature before the next room is fully loaded. When the next room finishes loading, there is one frame of game play before the R-Tank activates.

This frame can be used to activate X-Ray, and although doing so would normally cause the less-useful "R-Mode", found many years ago by Kejardon, G-Mode can be achieved instead if the input used for activating X-Ray is released within a ~3 frame window, while the R-Tank finishes refilling Samus's energy.

This enables control over Samus, but leaves some properties of X-Ray active - for example, the game is unable to execute any PLMs, such as crumble blocks or screen scroll controllers (which is the reason the camera doesn't follow Samus during this mode), meaning activating too many PLMs will cause the queue to fill up and make most of them nonsolid. Thus, through G-Mode, Lower Norfair is easily accessible through what is normally its exit by jumping through the nonsolid pillars and crumble blocks.

The mode is disabled whenever X-Ray is activated again, and since doors are also PLMs, they will not open while the mode is active (excluding the initial door, which stays open when the mode is first activated, allowing the mode to persist into the room you were originally in).