A Screen KO (手前やられ, Forefront defeat) is a special type of KO which has a chance of occurring when characters are launched past the upper blast line. In contrast to a Star KO, the character instead falls into the foreground and appears to crash into the screen, before they are KO'd at the bottom, which is how these KO's got their name.
Whether a character is Star KO'd, Screen KO'd, or merely blast KO'd is mostly random. In the first three games, Screen KOs are considerably rarer than Star KOs; as a result, Screen KOs rarely involve two or more characters at once. From Super Smash Bros. 4 onward, the frequency of Screen KOs has been increased, especially in the 3DS version of Smash 4, to be about as common as Star KOs.
Differences between games
In Smash 64, characters yell out their Star KO scream and fall down between the front of the stage and the camera, getting KO'd by the bottom blast line afterward. Depending on the camera angle, this may not always be visible. The distance the character is from the camera is chosen randomly — sometimes doomed characters appear to be falling normally, while at other times they are just a quick flash of color going down the screen. Screen KOs have the same duration as a Star KO. Unlike the other games of the series, Screen KO'd characters do not actually hit the screen in any way.
In Melee, all characters, with exception of Mr. Game & Watch, have a unique tumbling animation for when they crash into the screen; upon striking the camera, the character also yells out one of their strong knockback groans, then gets KO'd by the bottom blast line without making any sounds. How close a character being KO'd is to the camera is no longer determined by randomness, but by the stage being played on. On Mushroom Kingdom II, for example, Screen KO'd characters are very close to the camera and thus appear much larger. With the introduction of Coin Battles, Screen KO'd characters also visibly drop numerous coins when they hit the screen.
While Screen KOs in 64 were roughly the same length as star KOs (around 2 seconds), Screen KOs in Melee are significantly faster than Star KOs (around 1 second). This difference is significant, and can potentially affect gameplay. For example, when a character is KO'd by Jigglypuff's Rest, getting a Star KO means that the character will not respawn fast enough to punish the sleeping Jigglypuff, due to the length of the Star KO animation. However, if a character is instead Screen KO'd, this provides them with more time to potentially get a solid hit on the vulnerable Jigglypuff. The Screen KO's shorter duration can also influence the outcome of matches that have gone to a last stock situation. If both characters are KO'd off of the top at around the same time and one is Screen KO'd instead of Star KO'd, the Star KO'd player will win the match due to random chance and the lengthier animation.
A bonus exists for getting Screen KO'd, Foresight, which grants the receiver 500 points for every time they are KO'd this way.
Flat Zone features a different animation for Screen KOs compared to other stages, where characters hit the screen in their tumbling animation instead of their standard screen KO animation.
In Brawl, with the exception of Meta Knight, King Dedede, Mr. Game & Watch, and Sonic, characters use a side version of their regular tumbling animations for a Screen KO, though the animations for the actual impact are not as nuanced as in Melee. Like Melee, Screen KOs are considerably faster than Star KOs, again potentially leading to some gameplay effects.
With the removal of strong knockback yells in Brawl, characters now either use their regular pain yells or remain silent when they hit the screen.
In SSB4, instead of using their tumbling animation, every character now uses a unique Screen KO animation depicting them flying towards the screen, hitting it face-first, then staying in place briefly before sliding down. Due to this new separate animation, several characters pose during their Screen KOs in a manner referencing their series, such as Kirby reusing a pose from Kirby: Triple Deluxe, Cloud using a pose similar to his official render, and Shulk hitting the screen with his back in order for the Monado to be visible. Characters who share the same base model tend to share the same Screen KO poses, such as Ness and Lucas. While Smash 4 re-added strong knockback yells that were absent in Brawl, Screen KO'd characters in SSB4 no longer make any vocal sounds when they hit the screen, and instead, a comical "thud" sound effect is played.
As a direct result of the new Screen KO's "pause", Screen KOs now take a very slight amount of more time to resolve than a Star KO, which is seemingly a change made to not affecting gameplay as much compared to Melee or Brawl. Furthermore, Screen KOs and Star KOs are both disabled during the final five seconds of a match and Sudden Death — characters will simply create the usual colorful blast after crossing the blast line. Blast KOs can still occur even if the match has no time limit or if it is in an early part of a timed match.
Several characters have different Screen KOs between both versions. The maximum amount of characters that can be Screen KO'd at one time is three.
In Super Smash Bros. for Wii U, Screen KOs are disabled on Super Mario Maker, Jungle Hijinxs (normal form only), Flat Zone X, Duck Hunt, Wii Fit Studio, Pac-Land, and Umbra Clock Tower, and players instead are either Blast KO'd or Star KO'd on these stages. Screen KOs are available in all stages except Super Mario Maker and Umbra Clock Tower in Super Smash Bros. for Nintendo 3DS.
Screen KOs retain their unique animations from Smash 4. They once again complete faster than Star KOs, which will affect gameplay. For the first time in the series, one attack can cause instant Screen KOs, which is Giga Bowser Punch, and the Beetle item will now always cause a Screen KO. At the end of the animation, the colored blast from a Blast KO now appears off the bottom blast line. However, there are still stages where Screen KOs can't occur. These stages in VS. mode are: