These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Accidental Innuendo: Many people have noticed Scott Pilgrim's testicles◊. Made funnier because, as the Major Spoilers review of Volume 6 pointed out, "Scott Pilgrim Grows a Pair" would be a pretty fitting alternate title... It's actually possible that this innuendo was not accidental at all.
Anti-Climax Boss: Lucas Lee. Scott asks Lucas to show off his skateboarding skills. Lucas wipes out and hits the curb. Scott wins by default.
Scott even comments afterwards, "That was the worst fight ever!" - though it's mainly because he couldn't pick up the Mithril Skateboard Lucas leaves behind.
Alternative Character Interpretation: The League of Ramona's Evil Ex-Boyfriends could be just a group therapy comprising emotionally destroyed people who loved Ramona Flowers. She broke all their hearts in the worst ways possible, and she didn't care how messed up they became. Gideon could be half evil and half broken; the rest just want to keep Ramona from doing it all over again and are messed up in thinking that beating her new potential love interests (Scott, for example) will break the cycle.
Done on purpose for the film adaptation, where if it was about Stephan and his band trying to make it big but Scott accidentally screws up by being strung on Ramona and they only get successful without him, just like his own ex-girlfriend.
Awesome Music: Not that we can hear the music, but come on, the fight with the first ex culminating in a song battle is pretty damn awesome.
Dare we mention "Invaders Must Die" by The Prodigy in the movie's trailer?
In Volume 6, the song Envy sings, and the lousy cover of "I'm a Believer" by Shatterband are very awesome moments.
Base Breaker / Die for Our Ship: Ramona has ended up becoming this in retrospect, due to sects of the fans preferring Scott to end up with Knives or Kim.
This can mostly be tied to the movie where Knives is shown to be a much more compatible girlfriend for Scott and even ended up with him in the original ending.
"Funny Aneurysm" Moment: In the fourth volume, Lisa mentions living off of credit cards and derides herself for doing so. Not long after the volume was released, the real-life credit crunch of '08 hit.
A rather meta example: You know that cool shirt Edgar Wright is wearing in the fourth trailer? After the release of Volume 6, turns out that's an official Chaos Theater shirt.
After reading Volume 6 and finding out at the end that Stephen Stills is gay, going back and reading Volume 5 has a moment like this when Young Neil refers to Stephen Stills as "Captain Homo", and it hits you that there was a whole other layer to Neil's face-punchingly dickish comment.
Though never emphasized by anyone (besides a very biased Knives), Ramona is noticably more "fuller" than the rest of the women Scott has dated throughout the series, especially apparent when she's in her underwear.
Also, Envy Adams, especially in Volume 6 after she reveals that her and Scott's break-up was a mutual occurrence and Scott simply white-washed his role in it out of the flashbacks seen by the reader in Volume 3.
Les Yay: Kim & Knives in Volume 4. Granted, they're drunk.
There's also Knives' fangirlism bordering-on-a-crush of Envy Adams.
Ramona constantly thinks about Kim in the comic, often responding with, "I like Kim".
Nightmare Fuel: Early into Volume 6, Scott was having another one of his bizarre dreams; this time he's all alone in the desert. He looks looks up to the sky to see an angelic Ramona Flowers swooping down and impales Scott with The Power of Love sword, pinning him to the ground and flies away. Then sky suddenly became dark and three monsterous figures appears out of nowhere and proceed to eat his limbs, with Scott being completely helpless to watch in horror as he suffers being eaten alive. After the monsters ate his arms and legs, he got a good glimspe of the monsters: it turns out the monsters were Envy, Knives, and Kim, each with razor-sharp teeth and a psychoticgrin (Knives might stick out to some with her smile.jpg-esque grin).
Paranoia Fuel: Subspace. People can get in your head and see your dreams. That's enough of a privacy nightmare when your girlfriend doing it, and worse still your nemesis can spy on you and mess with your memories. Or, from Ramona's perspective (which is never really explicitly addressed), a Living Doll Collector ex who is stalking and trying to kill your boyfriend so he can have you all to himself. And is implied to have done the exact same thing to others. Creepy.
Wallace's Mystery Shop; buying the Bionic Arm (which really, should just take 2-3 runs through the first stage) drastically reduces the difficulty of the game; let alone the other items sold there.
The strength book available at the bookstore actually provides slightly better value, and each book is about 1/5 the price of the Bionic Arm, so you can increase your strength more gradually.
If you pay off the late fee at the video store in the first level, you can buy extra lives for only $4.95.
Along with raising all your stats by 10 for only $4.95 a pop. You cap at 100.
After maxing-out your stats, why not blow $4.95 for 1,500 XP to sky-rocket your characters to Lv. 16?
There's also the code that lets you use the Power of Love sword outside of the final stage, which helps because of the range it gives.
The "suicide for 25 $2 coins" code can be exploited with any snack (Chewing Gum in the first level is very cheap) to gain instant cash. It's even funnier considering the suicide code is a shout out to the Konami Code.
A more strenuous alternative involving the use of an external memory storage device, a "dummy" Xbox 360 or PlayStation 3 profile, and Save Scumming can allow those to double their cash.
Goddamned Bats: Particularly in the Twins' stages. Also the swooping birds in Level 6. On a less literal level, there's the paparazzi enemies in Lucas' stage, who don't do much damage but can and will repeatedly stun you with their camera flashes, and the domino-masked "thief" foes in Roxy's stage, who like to bodycheck you and steal your coins. And they're fast, so can do it multiple times.
And the Medusa Heads in "Subspace Highway?" (right before Gigadeon).
Ho Yay: We see Wallace making out with Jimmy in the background of the first boss battle.
It's the Same, so It Sucks: The Wallace DLC pack. Besides the online multi-player fans of the game were begging for, Wallace is nothing more than a re-skinned Stephen with rainbow effects. It's disappointing considering Ubisoft could've made Wallace a unique fighter, but they cheaped out in the end. It doesn't help that the DLC is also $5 considering what you're paying for.
Narm: Go fight some paparazzi in the second stage with the blood code activated. You'll see...
That One Boss: While a lot of them have the potential to be that one boss, Nega-Scott is generally regarded to be the most difficult of them all. Unless you really know what you're doing, tackling him alone is begging for an ass whooping.
There's also Todd Ingram giving Scott (and the other characters) the finger, some people may object to Kim and Knives kissing, and Todd'sTetsuo-esque attack and Gigadeon may scare some younger players.
Let's not forget that zombies are all around the later half of Level 6 and the unlockable Survival Horror mode.