The move can be charged for about three seconds, and once let go, Luigi launches himself sideways like a rocket, with the distance and damage being based on how long the move is charged. At full charge, the move can reliably KO under 150%; however, it is not often used to KO due to being extremely predictable and taking too long to charge. Despite this, it still remains a very powerful KO move, potentially rivaling the Super Jump Punch as Luigi's best KO move.
The move also has a small chance to "misfire", an effect officially known as Overzealous Green Missile. A misfire's distance and damage will not be affected by how much it is charged, with both being greater than even a fully charged regular Green Missile. The probability of misfiring is 1/8 for Melee and Brawl and 1/10 for SSB4 and Ultimate. When one occurs, the move's animation will have a noticeable fire/rocket effect. In Melee, Luigi's eyes will close as if he was struck, as opposed to being halfway open during a normal Green Missile; SSB4 introduced a unique sound effect, and Luigi spins as if reeling in Ultimate. In Smash 4 onwards, Luigi can never misfire in Home-Run Contest.
A misfire can allow Luigi to cover horizontal distances significantly farther than normal; however, as implied by the name, a misfire is not always beneficial. For example, if the move is aimed at an opponent who dodges and the move misfires, Luigi will likely travel horizontally a long distance off the stage even if the move was uncharged, making it very hard for him to get back on (as well as leaving him exposed to edgeguarding). In Melee, the spontaneous misfire fires Luigi extremely far, nearly three times the distance of an uncharged Green Missile and longer than Final Destination, potentially causing an SD. This has been toned down from Brawl onwards to about twice the regular distance, lowering the chance of an SD occurring.
As Luigi's regular up special recovery move, Super Jump Punch, gains no horizontal distance whatsoever, CPU Luigis in Melee are coded to use the Green Missile instead to recover. However, even at CPU level 9, they will never switch to the Super Jump Punch once they drop below the level of the stage, which will always cause them to uselessly repeat the Green Missile over and over below the edge and result in an avoidable SD. This is most visible when fighting a CPU Luigi on Mushroom Kingdom II. Additionally, the CPU will never charge the move, making it even more likely to come up short. High-level CPUs in Brawl are capable of properly combining the two recovery moves (though lower-level ones will only use the Super Jump Punch).
Super Smash Bros. Brawl allows Luigi to hold this move at full charge indefinitely. If a partially charged one hits a wall, occasionally Luigi will get stuck for a brief moment and have to pull himself free, accompanied by a spring noise as his body bobs up and down for comedic effect. Also added in Brawl is the lesser-known fact that the move gives Luigi a slight vertical boost if used right after a jump. This may be related to Luigi's normally slow falling speed. If the trick is used when Luigi is metal or is wearing a Bunny Hood (both of which increase a character's falling speed), the boost will be much higher.
Super Smash Bros. 4 still allows the move to be held at full charge, but if Luigi's on the ground, he will cancel the move automatically via a panting motion after a certain amount of time, leaving him vulnerable for a short time. The vertical boost gained from using the move right after a jump is retained from Brawl. Additionally, the move has a new aesthetic sound while charging, which resembles the whistle of a kettle boiling. Aesthetically, unlike in past games where Luigi orients himself to his left whenever he uses the move, he now always faces towards the screen during its whole animation.
In Super Smash Bros. Ultimate, the move is almost the same as the previous games in which it appeared, but his energy effect now moves toward him than away from him, and his stance is changed. He also spins if he misfires. Misfiring, however, no longer gives any height. This makes the move put Luigi under the stage if used too close to it and/or too low.
In Melee, an uncharged Missile will travel farther if the control stick is tapped, rather than just held, during the input. In SSB4, Green Missile will also charge faster and deal more damage. In the same game, the indicator of Luigi's charge is shortened from 6 to 5 flashes, and the damage is increased from 6% to 9%.
The move is similar to Skull Bash, though Skull Bash cannot misfire.
Special Move customization was added in Super Smash Bros. 4. These are the variations:
The Green Missile is an original move, and nothing like it has appeared in any Mario game released before Super Smash Bros. Melee. Luigi has been known to have a comical style though, as mentioned on the official Smash Bros. website, which could explain the Green Missile's rather silly execution. It also could have come directly from Pikachu's Skull Bash.
Like the Egg Roll, the Green Missile has appeared in games released after the move's introduction in Melee. Luigi would later use this move as one of his attacks in Mario Sports Mix and as his Special Move in Mario & Sonic at the Olympic Winter Games. Unlike the Egg Roll, however, the resemblance may just be a coincidence, as it is not used as a named special move. Luigi did a similar move in The Super Mario Bros. Super Show! episode The Adventures of Sherlock Mario.