WARNING: The following contains spoilers for Episode 9 of Komi Can't Communicate, "It's just a Country Kid," now streaming on Netflix.
Throughout Komi Can't Communicate, protagonist Shoko Komi has been working on overcoming her extreme social anxiety and improving her communication skills. Over the course of her journey, she's become close friends with Hitohito Tadano and Najimi Osana, and with them, Komi acquired a lot of new experiences she otherwise may not have obtained. Episode 9 continues this trajectory when her classmate Omoharu Nakanaka invites her and her two friends to play video games at her house.
The game the four teenagers end up playing is Swamp Bros -- a very obvious parody of Super Smash Bros, complete with parody versions of iconic Nintendo characters. Some of these characters include parody versions of Mario (Majio), Luigi (Chūnii), Yoshi (Tadashi) and Princess Zelda. Najimi ends up playing as Majio, with Nakanaka playing as Chūnii and Tadano as Tadashi. Komi -- through trial and error -- ends up picking the parody version of Zelda as her character.
The premise of Swamp Bros is the same as the real-life Super Smash Bros game where the players all battle each other on a fighting stage with the goal of knocking opponents off; the player that's left standing wins. The Swamp Bros version of the fighting stage is nearly identical to that of the Super Smash Bros version, complete with floating objects for players to land on to save themselves from losing. The only thing different about the Swamp Bros version is that players have to avoid falling into the swamp, which is the "out of bounds" of the fighting stage.
In addition to parodying a popular Nintendo fighting game, even the Komi Can't Communicate characters parody different types of gamers. Najimi and Nakanaka, for example, parody two different types of competitive gamers: Najimi parodies the gamer that targets the inexperienced player because they're easy to beat and because that's one less person to fight. Nakanaka on the other hand goes after the other competitive gamer -- in this case, Najimi -- with the goal of upstaging them. In contrast to both Najimi and Nakanaka is Tadano, who tries to teach the highly inexperienced gamer, Komi, how to use the buttons on the controller to control her character's movements. The dynamics of all four teenagers yield hilarious results.
True to form, Najimi goes after Komi while she's trying to figure out how to use the controller to move her character, but is immediately intercepted by Nakanaka, who is determined to beat Najimi at the game. While Najimi and Nakanaka brutally fight each other to prove who's best, Komi figures out how to get her character to walk -- only to end up walking into the swamp, nearly disqualifying herself from the game. Tadano manages to explain to her how to get out of the swamp, but being covered in mud slows down her movements.
While Komi presses random buttons on her controller to get the mud off her character, she unwittingly hits Tadano's character, prompting her to apologize each time. The moment she figures out how to remove the mud from her character, some of the mud ends up landing on the eyes of Najimi's character, temporarily incapacitating it. This gives Nakanaka the advantage to knock Najimi's character off stage, which he does successfully, causing Najimi to lose.
Although Nakanaka prides herself in having finally beaten Najimi in a game, Najimi is quick to dismiss the victory, pointing out that she only won thanks to Komi temporarily incapacitating their character. Nakanaka in turn refutes this argument by pointing out Najimi is a sore loser and would've still complained even if they had lost in a fair game.