Differences between the movie and the graphic novels.
Lisa Miller and several other characters are not in the movie although she is in the animated short.
Where the book series takes place over a year, the film takes place over a few weeks.
In the graphic novel series, Scott begins as a 23 year old and eventually turns 24. In the movie, Scott is 22 and because the movie takes place over a shorter period of time, and he never has a birthday.
Ramona changes her hairstyle eight times throughout the book series, where in the movies her hair color is changed only three times.
Scott doesn't receive a letter from Patel. Just the E-Mail.
In the party scene where Scott meets Ramona, he (instead of shaping out her hair) draws a picture when asking Comeau about her. The picture was actually drawn by Bryan Lee O'Malley.
The scene where Scott urinates and his Pee Bar depletes is now in one of the dream sequences, instead of when he was at Sneaky Dee's. (and, speaking of Sneaky Dee's, that place is not in the movie) Also, the Pee Bar's design differs from the movie and comic. In the comic, it simply reads, "Pee", and it is longer and is designed to look more like a bar from a retro game. In the movie, it reads, "Pee Bar", and it is smaller and is just a simple yellow bar.
The first evil ex battle Matthew Patel originally had the line "That doesn't even rhyme!" In the movie, Scott says this.
Patel's loss is less humiliating in the movie. Instead of being an easy win for Scott, Patel actually gives Scott a good beating before being knocked out.
Crash and the Boys do not perform the songs Zog or Last Song Kills Audience.
Crash and the Boys are actually incinerated in the movie by a stray fireball from Patel.
Patel drops $2.40 instead of $2.10 in comic.
After the fight against Patel, Scott was seen talking to Ramona on a bus when she told Scott about her exes. In the comic book this took place on the TTC subway, persumably Yonge line northbound as its destination reads Finch station.
In Book 2, Knives fought Ramona for the first time in a reference library. In the movie, they only fought in the Chaos Theatre during Scott and Gideon's battle.
Lucas Lee in the books was a decent guy who didn't strive for the defeat of Scott. In the movie he is more of an asshole, never giving Pilgrim the break he offered, instead tricking him into letting his guard down so he could punch him.
Scott's fight against Lucas Lee started with a battle against his stunt doubles in the movie, but Lee still does the dare.
Scott does not receive the mithril skateboard after defeating Lucas Lee.
The plot involving Todd cheating on Envy with Lynette is left out.
Knives is punched by Todd Ingram instead of Lynette Guycott.
After Todd starts fighting Scott, he throws Scott through the wall of Lee's Palace into the back alley, and after a brief scene, vegan police immediately arrives and strips Todd of psychic power, ending the fight.
The scene of Honest Ed's was not in the movie.
The Vegan Police are brought in a different way. Scott tricks Todd into drinking a cup of coffee containing half and half, which then causes the Vegan police to come crashing through.
Mr. Chau is never seen in the movie
Scott's fight with Roxie Richter doesn't involve defeating her with the Power Of Love, which he first gains in the climax.
In the movie, Roxie's name is spelled Roxy, possibly a reference to her being the 4th evil ex (Roxy is 4 letters).
When Scott finds out about Roxanne and Ramona's relationship, we see a meter in his head which goes from, "No clue" to, "Gets it". In the comic, a baby chicken hatches from his brain when he finds out.
Part of the fight against Roxie involved Ramona controlling Scott's movements to attack. This was based off a 2006 FCBD (Free Comic Book Day) comic involving poster copies of movie star Winifred Hailey.
Roxie does not explode into little furry creatures like the the series, instead bursts into coins.
Scott meets Roxie (evil ex number four) for the first time in the movie before fighting Todd (evil ex number three).
Scott earns a Extra Life after defeating the Katayanagi Twins in the movie, rather than earning it from Todd Ingram.
In the movie, Roxie was defeated after Scott poked the back of her knees. In Book 3, he does the same thing to Envy, except only paralyzing her. Also, the battle with Roxie occurs at the after party for the The Clash At Demonhead show.
Instead of fighting Envy with a hammer, Ramona uses the hammer to fight her evil ex Roxy.
Scott's fight with the twins is a music battle, with Sex Bob-Omb fighting the twins' electronic music project.
The twins don't speak, either. (this is due to the fact the actors don't speak English)
In Book 5, Ramona confronted Scott about whether he cheated on her with Knives or vice versa. In the movie, Scott accidentally blurted that he cheated on Knives with Ramona.
Sex Bob-omb never splits up and Gideon turns out to be their sponsor, although Scott is replaced by Young Neil.
Scott remembers less of the actual truth of how him and Kim began dating.
Instead of random gigs, Sex Bob-omb are involved in a band tournament for a record deal.
Ramona never receives the Power of Love during Scott's fight with Gideon.
Gideon never steals the Power of Love from Scott. Instead, it breaks and he (instead of getting The Power of Understanding like in the comics) gets a different sword called the Power of Self-Respect, which also breaks during the fight.
In the movie, Scott came to terms with his own faults and thus decides to fight for himself against Gideon, gaining the sword "Power of Self-Respect". In Book 6, he admitted and understood that he was no better than Gideon in terms of relationship, thus earning him the sword "The Power of Understanding".
There is no mention of Gideon tampering with Scott's memories.
Scott and Negascott's fight doesn't happen and Negascott appears after the fight against Gideon but even then, the two get along. Their fight seems akin to fighting games in which after facing the last boss you then 'face yourself' by then fighting a clone of your character, which is different from the purpose of their fight in the comics.
In Book 6, Ramona was absent during the fight between Gideon and Scott, until Scott was revived due to his Extra Life. In the movie, Gideon held Ramona hostage via mind chip, luring Scott to the final battle.
In the movie, Ramona knees Gideon in the balls whilst saying "Let's both be girls." In the books, it is Envy who does the same exact thing to Todd, whilst Ramona never does this.
In the climax of the fight against Gideon, Scott and Knives defeated him in the movie, rather than Scott and Ramona doing so in Book 6.
In the original version of the film, Scott actually ended up with Knives instead of Ramona, however, this alternate ending was scrapped.
Stephen Stills doesn't admit he's gay to his friends in the movie.
The Glow from volume 6 isn't mentioned in the film. Also the details about Subspace are quickly mentioned when Ramona delivers Scott his package, and they flirt with going through Subspace a few times in the movie, but it is not entirely explained nor used as any plot points like it is in the comics.
The Subspace Backpack is not explained either. The only thing we see about the Subspace Backpack in the movie is just Ramona pulling her hammer out of there.
Gideon's 6 other exes are not in the movie.
In the movie Gideon bursts into 7,000,000,000 coins instead of 7,777,777 coins.
In the Movie, instead of using "The Glow" to tamper with Scott's and Ramona's emotions, Gideon uses an electronic device stuck to the back of Ramona's neck.
Gideon, the cat that Ramona owned that ran away in Book 2 but Scott found and kept is never mentioned or seen in the movie.
When Gideon impales Scott, he does not bleed at all, whereas in the comic, he does.
When Scott comes back using the 1-Up he got earlier, instead of immediately coming back to where he was when he died, he has to start over from the part where he got the 1-Up (although it is fast forwarded to the beginning of the fight).