So, the way the show starts is that there's this VRMMORPG (Virtual Reality Massively Multiplayer Online Role Playing Game) coming out called Sword Art Online. Bunch of people log in, can't leave, big asshole dude in the sky says "Die in the game die in real life. Try to forcibly disconnect in the real world die in real life. Make it up all 100 floors of SAO, win the game, you get to leave." So immediately the stakes are raised to the absolute maximum, which immediately destroys the show as a whole. Kirito decides, instead of teaming up with this one dude (named Klein) and his friends in a party, he'll just go off on his own. So we already have brooding, loner protagonist. That's fine, since I assumed we'd be finding out more about him as time went on.
Next episode, they find out where the dungeon is on the first floor, bunch of people organize a raid party, Kirito gets involved, meets Asuna (she'll be important later). Anyways, he helps her figure out how to play the game, which doesn't make any sense given that we find out she's one of the best fighters in the show (despite which she gets bodied later on but we'll get there), but hey we need our MC to help girls so he can be cool. Anyways it's in this instance that we find out Kirito was a beta tester, and apparently beta testers are hated because they knew the ins and outs of the game and didn't help people out enough (some-thousand people died after the first couple weeks). Despite the fact that everyone was given an instructional guide created by the testers. Anyways, the testers are now called "Beaters" because cheater + beta tester = beater. So, they get to the dungeon, Asuna and Kirito kill the monster, and Kirito takes the loot. One dude who is an asshole states that Kirito let their leader die (he didn't. The leader was bad) because some stuff got changed about the boss of the dungeon and it's Kirito's fault somehow. So then Kirito decides to own up, state that he's better than everyone because he got to level 6 of SAO on his own in the beta, and then tells everyone to fuck off including Asuna.
This is my first huge problem with the series. Kirito playing the Dark Knight, the whole "I'll be hated so everyone will unite against the common threat" character. Now that's fine, except IT DOESN'T MEAN ANYTHING. First of all, if Kirito was so good, why didn't he just go kill the boss himself. He's trying to hide his skill FOR NO REASON. And this isn't the first time he'll do this. Maybe he wants friends and doesn't want to scare them off, but he has no personality anyways. His only character trait is "good at viddy gamz," which basically means he's EVERYONE's best friend in SAO. He's an asshole for hiding it. That's not the true issue I have with this plot point, though. The main issue is that his whole Dark Knight bit doesn't actually mean anything. It doesn't. This never comes up again. No one ever acknowledges it ever. It's a useless plot point made to make Kirito "cool," because number one Anime Insert Fantasy Trope "I have the world on my shoulders and must therefore brood because issues and things" has to be present. He mopes about being good at things. The fuck?
Anyways, next up is an episode where he hides his level from a guild so that he can join them. Friends, I guess? I'd buy it, but later we find out Klein and his friends are still very much alive. So, why wouldn't he join them? Instead he joins a much lower guild and helps them get good, which I like. He's helped Klein get good in the beginning, so it's in line with whatever cardboard he's made out of. Honestly, this is the best episode in the show. Anyways, he wanders off, meets up with Klein who tells him "It's not your fault." See, timeskips occur frequently in the beginning of the show, and it's a huge issue. In this case, we think "Oh shit Kirito did something." Anyways, the leader of the guild Kirito's a part of leaves to go buy a house. The other guild members want to go get beefier on a higher floor, Kirito goes with. Now, he doesn't want them go, but instead of telling them "I'm a higher level and you'll all die" he goes on with it. They enter a trap room and all of them are dead except Kirito. He feels super guilty because the ONE GIRL IN THE GUILD (this is a theme) dies, and he promised her she wouldn't. Anyways, he tells the guild leader, who then kills himself. So, feeling guilty, he tracks down a special item to resurrect her, it doesn't work. Klein gives him a pep talk, it doesn't work. He leaves.
Next episode, he meets a girl who falls in love with him, helps her out. We never see her again, even though she's pretty cool and has a dragon. It's a useless episode aside from establishing that Kirito basically just chills on low-level floors helping people, he's over powered, and people call him "The Black Swordsman." Apparently a fear-inspiring name, but it doesn't really come up again.
So, as time goes on, Asuna and Kirito spend more time together and bond. Kirito meets a blacksmith who builds him a good sword, she falls in love with him and then gets over it because he's in love with Asuna who is in love with Kirito (for no damn reason). So, they're battle buddies, Kirito saves Asuna's life, and then awkwardly offers him sex, because it's the only reward a woman can give a man. Honestly it's weird and they're 15 and it's weird. So then they decide to spend they're lives together and get married.
Except Heathcliff, the leader of Asuna's guild, and the main guild clearing floors, wants Kirito in his crew because Kirito unlocked a super secret ability: Dual-wielding. Now, this ability is dumb. Why? Because in order to get it, you have to have the "fastest reaction time in the game." Now, this doesn't make sense because Asuna is stated to be faster than Kirito. In fact, Kirito's fighting style doesn't even make sense. He wields a one-handed sword with no shield. When asked why, it turns out he had this super-secret ability just hangin around. Not the whole time though, so his fighting style is still never revealed. Anyways, the main character gets an exclusive power-up and fights for whether or not Asuna can leave the guild (she wants to because of the need to awkwardly sex her man). Also, did I mention that Asuna has max cooking skill? That's right. She's amazing at cooking AND rewards men who help her out with awkward sex. Perfect.
So Kirito loses (because Heathcliff cheated), is forced to join the guild, and then goes on vacation with Asuna to find a house and live in peace. They have a child (don't ask. I don't want to explain it) who then dies. They go back to the guild, do a raid, and discover that *gasp* Heathcliff is the creator of the game. So, Heathcliff paralyzes everyone except Kirito, forcing him to a fair duel. Heathcliff wins, everyone has to continue to the 100th floor and beat him. If Kirito wins, the game is over. Kirito also makes a deal that Heathcliff has to reprogram the game so Asuna can't kill herself (because that's what she was going to do if Kirito lost. No point in living, after all). Heathcliff kills Asuna to bait Kirito, Kirito wins because bullshit. SAO over.