After being chastised for not having an email address, Marge gets into the Internet and gets involved in an online role-playing game, where she defeats the world's biggest enemy: her son, Bart. Meanwhile, Homer becomes a kids' soccer referee and rigs the games so Lisa can win.
- Accidental Murder: The Shadow Knight accidentally kills Marge's character when he pulls his flail back in the process of destroying his renovated trophy room.
- Amazingly Embarrassing Parents:
- Marge ends up making a fool out of Bart the Shadow Knight.
Bart: Mom, you're making me look bad in front of my minions.
Marge: If they think less of you because of me, then they're not really your minions.
- Homer acts like a player during his first game as a referee and Lisa becomes upset.
- And There Was Much Rejoicing: The players of Earthland Realms sing a happy ditty after they kill the Shadow Knight whilst dancing around his organs.
- Badass Baritone: The Shadow Knight's voice is very deep when his helmet is on, not so much when it is off.
- Beware the Silly Ones: Bart may sound like a typical online gamer, but when the Shadow Knight starts smashing up Marge's redecorating, he's strong enough to accidentally kill her in with a single blow.
- Big Damn Heroes: The Shadow Knight saves Marge from Ralph, Jimbo, and Kearney when they prepare to eat her.
- Bloodier and Gorier: The Shadow Knight's death is pretty gruesome by the standards of this show. It involves him being stabbed in the eye, kicked in the "jewels", beaten with his own severed limbs and disembowelled. Then people dance around with his entrails as if they were party streamers.
- Bowdlerize: In the UK, the Channel 4 reruns of this episode cut out the scene where Bart saves Marge's avatar from Jimbo, Dolph and Kearney by chopping their heads off.
- In addition, the scene where the other players celebrate killing the Shadow Knight by maypole dancing with his intestines is edited out.
- Continuity Nod: When Marge looks herself up on Google, three of the website links she recieves from the search engine reference her brief career in real estate, her time in Camp Landaman, and her popsicle stick sculptures earlier this season.
- Cruel and Unusual Death: According to Moe, the Shadow Knight once beat his character to death with his own life bar. The Shadow Knight himself later gets an incredibly bloody death when he is blinded, loses his limbs, and later gets disembowelled.
- Damned by Faint Praise: Lisa to Marge when she discovers the Internet.
Lisa: You're just like Christopher Columbus! You discovered something that millions of people already knew about.
- Didn't Think This Through: When Marge said she'd tell everyone how the Shadow Knight gave up some of his life force to revive her character, she didn't consider that his enemies would take advantage of his weakened state. She doesn't get the chance before the other players figure it out and kill him while he's weak.
- Football Hooligans: Lisa realizes how crazy soccer has made her when she watches a documentary about soccer riots, one scene showing a British riot that lasted for decades, and another one in South America where the statue of the Virgin Mary came to life and "beat the living snot out of everyone".
- A gag in this episode has the Lovejoys telling their daughter Jessica to win and "save our troubled marriage". The very next episode "The Boys of Bummer" has the Lovejoys having bed troubles.
- Homer's eventual refusal to favor Lisa during his time as a referee starts the main plot of "You Don't Have to Live Like a Referee".
- Groin Attack: In the Earthland Realms, Mr. Largo (in the form of a satyr) gets one in on the Shadow Knight when the characters show up to kill him.
- Heel Realization: Lisa after she watches the documentary and realizes how insane soccer has made her, and she admits to Homer was right to kick her out of the game.
- I Resemble That Remark!: Moe is annoyed that everyone in the game confuses him for a troll. He proceeds to go under a bridge and start shouting Angrish.
- Jerkass Has a Point: Bart killed Marge in a fit of rage after he grew tired of her antics. However, he only reached his Rage Breaking Point after she brought the Hello Kitty expansion pack and threw away all of his gear. Since Bart was the best player in the game, getting that gear would have required some serious Level Grinding, and Marge destroyed hours, possibly even days of his work.
- Kung-Fu Jesus: Or in this case, a statue of His mother, the Virgin Mary.
- Nepotism: Subverted. Lisa believes this will happen to her when her father becomes the referee, but gets angry when Homer gives her a yellow card for misbehaving, and angrier when Homer gives her a red card for tearing the yellow card in half.
Lisa: You can't give me a yellow card! You're my father!
Homer: When I put on these shorts, I'm not your father anymore. And judging from how tight they are, I'm not anyone else's either.
- Passing the Torch: After Bart the Shadow Knight is killed, Marge becomes the new Shadow Knight.
- Please Wake Up: After the Shadow Knight accidentally kills Marge's character.
Shadow Knight: Mom? ...Mom?
- Prefers Proper Names: Parodied. Cletus would rather be called a "hillWilliam" than a "hillbilly."
- Reality Ensues: Bart gives up two-thirds of his lifeforce in order to bring Marge back from the dead. The Shadow Knight has been shown to be a person who ruthlessly kills people in the game completely unnecessarily and often times just does it for his own amusement, and it's implied he has been doing this for a long time. The second they figure out that the Shadow Knight is now terribly weakened, they immediately storm his castle to finish the job.
- Redemption Equals Death: Bart the Shadow Knight brings Marge back to life with two thirds of his life force. This could well be interpreted as the Shadow Knight choosing to die as atonement for his prior actions.
- RPG Episode: The main plot is about Marge discovering the Internet and joining an MMORPG.
- Screw the Rules, I Have Connections!: How Lisa technically gets away with many of her actions, as Homer proceeds to give players who tackle her a yellow card even if Lisa is faking it.
- Special Guest: Brazilian football great Ronaldo, who dons a Real Madrid kit (though, when the episode premiered, he had already been transferred to A.C. Milan; unfortunately, there wasn't enough time to make this change).
- Bart's character, the Shadow Knight, is visually based on Arthas the Lich King from World of Warcraft.
- The MMO game's title Earthland Realms sounds like Forgotten Realms, one of the world settings of Dungeons & Dragons.
- Marge decorates Bart's room with Hello Kitty items.
- Stealth Pun: The word "gamer" in the title is an anagram of Marge's name.
- Take That!
But to get you that DVD, I had to become a PBS
subscriber! Now I'm paying for crap like American Masters
- Truth in Television: Homer gives Lisa a DVD about football riots, which opens with a fictional riot between fans of Manchester United and a fictional club called Sussexton Hamptonshire-on-Leath in 1985. In 1985, football hooliganism was at an all-time high in England, and an incident caused mostly by Liverpool supporters before the 1985 European Cup Final at Heysel Stadium in Belgium that saw 39 people - most of them supporters of Liverpool's opponents that night, Italian club Juventus - killed, and 600 people injured, resulted in English clubs being banned from European competitions until the early 1990s.
- Worth It: When Bart's enemies in the game are about to kill his character, he threatens to egg their homes in real life. Ms. Krabappel says it'll be worth it before stabbing him in the eye. Mr Largo says he lives in a loft right before he delivers a Groin Attack.
- Worf Had the Flu: The only reason the Shadow Knight falls before all of the other characters is due to the fact he lost two thirds of his life force to bring Marge back to life along with sheer numbers, despite the fact he still technically should have been able to fight them.