Screw Attack

Screw Attack is an item in Metroid Prime 2: Echoes and Metroid Prime 3: Corruption. Its appearance in Echoes is the first appearance of Screw Attack in a 3D Metroid game and it allows Samus to cross large horizontal gaps using up to five individual Screw Attacks at a time. It also has damaging properties, with many enemies and even certain bosses in Echoes being vulnerable to the attack.

In Metroid Prime 2: Echoes, Screw Attack is a required item for beating the game due to the Screw Attack Walls that are needed to climb the room Sanctum Access.

Overview

Mechanically, Screw Attack in the Prime games is less versatile than in its 2D counterparts, at the tradeoff of it being more powerful. In order to activate Screw Attack, the player needs to have pressed B at least 2 times, and on the third B press, be in the air and moving forward. Once in Screw Attack, the player has limited control over Samus wherein turning the analog stick right or left will move Samus towards that direction when doing one of the Screw Attacks. The player has an upward of five uses of Screw Attacks, after which Samus is forced to fall. The quicker a Screw Attack is performed, the less distance she moves overall, at the tradeoff of having more speed. The slower a Screw Attack is performed, the more horizontal distance is crossed, at the tradeoff of having lesser speed. Thus, optimal Screw Attack movement depends on the tradeoff between how much distance you cross and how fast you're going while in the Screw Attack sequence. Additionally, damage taken from Dark Aether's atmosphere is reduced while in Screw Attack.

At the end of the Screw Attack sequence, Samus will fall. This happens if the player presses B too quickly, has exhausted all five of their jumps, or bonks on a wall. It is important to note that Samus will not transition out of the Screw Attack sequence until she lands on a standable spot. If Samus never lands on a standable spot, the game will be effectively softlocked, forcing the player to reset. This means that if Samus falls and is out of bounds, she can easily fall below the bottom of the room and keep falling indefinitely. The same effect can also occur if Samus lands on a piece of collision out of bounds that is not standable.

Screw Attack does 36 damage per frame in Metroid Prime 2: Echoes. Certain bosses, including every Dark Samus fight and the first and third phases of Emperor Ing are vulnerable to Screw Attack, leading to major timesaves in speedruns. Certain objects can also be damaged or destroyed with Screw Attack that aren't obvious, such as the light crystal in Crypt, the crystal-activated door in Main Reactor, as well as the rubble in Main Gyro Chamber. It can also be used to destroy every seeker door in Metroid Prime 2, leading to development of seeker skip.

In the original release of Metroid Prime 2: Echoes, the hitbox that the game uses for Screw Attack is the same as the hitbox of the Morph Ball. Consequently, this means that in any Morph Ball tunnel that Samus can fit through, she will be able to go out of bounds once the game goes back into first person mode and changes her hitbox. This can also be done in certain tight spaces, such as the one in Dynamo Works. This was patched in the Trilogy release of the game.

Screw Attack Without Space Jump

The behavior of Screw Attack changes when Samus doesn't have the Space Jump Boots. Because the game doesn't expect you to get Screw Attack without Space Jump, its mechanics are far more difficult to utilize.

The Z-Axis

The Z-Axis is a variable that the game uses to determine the range at which Samus can perform one of the five Screw Attacks. Note that this is not to be confused with Samus' own Z-Axis, which is independent of the Z-Axis that Screw Attack uses to function. When one of the game's regions is loaded, this value is set to zero. Normally, the Z-Axis automatically updates whenever Samus performs a Screw Attack, but if playing NSJ, this value cannot be updated by the player. If Samus is too far below the Z-Axis, she will almost immediately cancel her Screw Attack before the player has the chance to perform a Screw Attack at all. The behavior is slightly different if she is above the Z-Axis, in which case she won't be able to perform a Screw Attack, but the Screw Attack sequence won't be immediately cancelled.

Screw Attack Walls can be used to update the Z-Axis even without Space Jump. It's easier to update the Z-axis to a higher value since Samus doesn't immediately cancel Screw Attack at higher values, but updating it to a lower value is also possible. This is used in Sanctum Access in order to climb the room without Space Jump, as the Z-axis in Sky Temple Grounds is below the map by default.