Piccolo only joins Goku in getting Gohan back in exchange for befriending him on MySpace.
Goku is notably much less intelligent than he is in the actual manga/anime. In episode 11, Chi-Chi mentions that Goku thought she was hiding "Cinna-Buns" under her shirt, while in reality she was pregnant with Gohan. And in episode 21, he "corrects" Gohan when he explains how Rabies is contracted, mistaking it for Tetanus, because "animals don't eat people, people eat animals. Silly Gohan."
Raditz knows that Piccolo is a Namekian and even mentions it to Goku before their fight. In the real series Nappa was the first to expose Piccolo's heritage.
Nappa has the intelligence and maturity of a child, much to Vegeta's frustration. But he actually went to Saiyan University, majored in Child Psychology and minored in Pain.
Nappa makes a lot of jokes about TV ads, like when he tells Vegeta "Tricks are for kids." and in the Butterfinger Special.
Krillin is more of a coward than he was misconceived in the original series, his failure to do well is also joked about. However, he will fight if he absolutely has to.
Piccolo only destroyed the moon because he thought it was mocking him.
Krillin also has a fear of Chi Chi castrating him. This is also the reason why he decided to go and recruit Tien, Yamcha and Chiaotzu, narrowly escaping Chi Chi before she arrived at Kame House. Additionally, he freaked out about this when Bulma let Gohan retrieve a dragon ball unescorted, fearing that Chi Chi will castrate him should Gohan get hurt.
Goku was killed by Piccolo's new attack only because he trusted Piccolo too easily to give him an advanced signal before firing.
Everyone already knows Piccolo is an alien from outer space, including Piccolo himself.
King Yemma is crazy about the phrase "mahogany", of which he claims his desk is made from.
Piccolo's attempt at unleashing Gohan's hidden potential via throwing him at a plateau isn't as successful; Gohan just hits the mountain with a loud splat, causing him extreme pain.
Piccolo took Gohan in only to train him so the two of them could take over the world; Piccolo didn't have a clue about the Saiyans headed towards Earth.
Popo is highly sadistic and intimidating, contrary to his gentle, friendly persona from the original series. It is hinted that his power is extreme since even the mighty Shenron called him his "master".
It was Goku who (very stupidly) told Raditz about the Dragon Balls by asking him if that's why he was on Earth, all of which Vegeta and Nappa heard through Raditz's scouter.
When asked about the Gravity of Kai's Planet, King Kai explains that the reason for the heavy gravity is that the space pirate Bojack is sealed in his planet. The true reason is because King Kai's planet is so small, the gravity is more intense according to the show.
Catching Bubbles and then hitting Gregory with the hammer weren't even part of King Kai's training session; Goku simply did those two things because he is easily distracted and very impulsive.
After hitting Gregory with a hammer, you can hear gregory yelling from offstage,"You psychotic bastard!"
In a bizarre twist with his stature as a "space pirate", Bojack is portrayed, at least verbally, as a stereotypical pirate, having the same type of accent, always starting off his words with "Yaurgh!".
Gohan is portrayed as having anger issues; he'll often snap and cuss at anyone, as he did after Piccolo is killed, he threatens to "SKULL-F**K" Nappa just before attacking him. His repressed anger resurfaced during his recovery in the hospital when his mother forbade him from going to Namek, he finally snapped and told her to "Shut her F***ing face!".
Goku gets back onto Snake Way by tricking Goz and Mez into telling him the way out of hell, rather than defeating them in a test of strength and speed (Which he would have had to do had it not been for Goz and Mez's stupidity).
Nappa convinces Vegeta to wait three hours for Goku's arrival, because Nappa wanted him (Goku) to "see them (Nappa & Vegeta) kill them (Piccolo, Krillin & Gohan)". In the original series it was the other way around. Vegeta forced Nappa to wait three hours, because he wanted to see what Goku could do.
Usually when Gohan is mad he explains the textbook definition of simple threats to his enemies before explaining the simple word or phrase to them like for example when Nappa kills Piccolo Gohan yells out "I am gonna eviscerate you and use your gastrointestinal tract as a condom whilst I fornicate with your skull!!" Nappa only responds with "Huh?" whilst Gohan explains "I'm gonna SKULL F**K YOU!!!" He did the same thing to Great Ape Vegeta, explaining in textbook definition "The bigger they are, the harder they fall".
In the original Nappa dodges Kurilin's Kienzan because Vegeta yelled at him, here Vegeta tells Nappa to catch it with his teeth, but instead he dodges it for some reason
Two factors led to Goku arriving to the battle against the Saiyans too late to save Piccolo's life:
Goku stopped at Princess Snake's palace for another huge meal (and ends up forgetting about the Saiyans), only to realize what he's supposed to be doing after Princess Snake reminded him.
After Goku returned to Earth, he requested Mr. Popo to teleport him to the battlefield, but Mr. Popo was pre-occupied with "making toast", so he's forced to take the Flying Nimbus.
Nappa is killed by Vegeta because he killed Piccolo (thereby making the Dragon Balls useless) In the original Vegeta told Nappa they didn't need Piccolo because they could use the Namekian Dragon Balls and instead killed him because he was crippled by Goku. In TFS' DBZ Kai Abridged, Vegeta killed Nappa because he (Vegeta) is a monkey.
Unlike the anime, Chaotzu is unaware that the Dragon Balls only resurrect people once.
In the original Dragonball manga and anime, Master Roshi was Korin's old student, but in Episode 11 when they visited Goku, Gohan and Krillin in the hospital, Master Roshi had no idea who Korin was, because when Korin introduced Mr. Popo to everyone, Master Roshi replied with "Did that cat just talk?".
Popo can possibly see the future, as he knew Krillin would die on Namek.
Gohan, Krillin and Bulma never really go to the fake planet Namek. Krillin simply dreamed the experience. Although, later on when Goku was in space he thought he found planet Namek but a few seconds later realised it was fake.
Rather than demonstrate it by channeling his energy in front of his opponents, Vegeta provides proof of becoming stronger from near-death injuries with an "Official Saiyan Handbook".
References to Cooler and King Cold abound in the abridged series, where in the original series Frieza's family was only introduced before the Cell Saga.
Dende is much more skeptical of their chances and is very cynical in general. He states that he is "weighing my options" between staying with Krillin and Gohan or going back to certain death.
Vegeta first learns that Frieza was behind the destruction of planet Vegeta, not from Dodoria, but from Frieza himself via "space-twitter" ("You really should have kept Frieza off the twitter")
Dodoria's gender is changed from male to female (by word of mouth only), and to Vegeta's incredible disgust, she considered to be the most beautiful and fertile woman on her home planet (Which Frieza blew up).
Zarbon is believed by many characters, including Frieza himself, to be homosexual. Despite this, he is in fact straight and has a girlfriend (whom Frieza is convinced is named "Chuck").
He could possibly be bisexual, as hinted at in a few scenes from the Bardock Abridged film: Once Frieza decides to confront Bardock alone Zarbon describes him as "a dashing rouge" to which a disturbed Dodoria responds with "What?"
Lord Guru is annoying, senile, and wastes a lot of time, instead of wise and intelligent. However, he appears to be in relatively good health, only dying just to pull a "dick move".
The Ginyu Force, rather than play "Rock Paper Scissors" to determine who fights who, have a game show, "Wheel of Death", where they spin the wheel and whoever it lands on, that contestant kills.
Instead of hating Vegeta for insulting him for his breath, Guldo hated Vegeta for treating him like a dog and even throwing dog treats at him.
Instead of Guldo just taking the dragonball from Krillin, TFS added to the scene where Vegeta tells him to destroy it, in which Krillin repeatedly hits it with his fist and screams in pain while Vegeta yells "Harder!"
Ginyu is contractually obligated to perform the Dance Of Joy by King Cold, and the Daddy's Little Princess Dance by Cooler. As well as the Dance of Solitude for no real reason.
Recoome is a professional wrestler (Or so he seems).
Burter and Jeice's ultimate attack is called Seizure-Procedure, which owns Krillin for the thirteenth time.
Goku punches Jeice in the face multiple times, instead of just once, and even cuts off Jeice while he is having a flashback in which Ginyu explains to Jeice what he should he do if he finds himself being punched in the face repeatedly, which was simply to dodge the attack.
Unlike the anime, Goku and Ginyu retain their voices after the body switch, the only difference being their accents spoken in each other's voices.
This is most likely based on the manga version, as Kurilin mistakes Ginyu-Goku for Goku for no reason.
Goku only threw the space frog in the path of Ginyu's body switch by accident; he was grossed out from seeing it on his hand, so he threw it.
Rather than let Space Frog Ginyu hop away, Vegeta crushes him under his foot, making his kill count "8 for 8" (thus TFS Vegeta is responsible for the death's of all TFS Ginyu Force members).
Frieza rips Nail's arm off 24 times, as opposed to only once in the original show. Many fan's believe this to be a reference to the episode's number.
Porunga only speaks Namekian, while in the original show he can speak English.
It was Krillin's idea to bring Piccolo to Namek, which Piccolo thought was a terrible idea.
Guldo is the one who reveals to Vegeta that Frieza can transform. In the original anime, it's revealed by Zarbon.
Burter is revealed to be a homosexual by Guldo during his conversation with Vegeta. In the series there is no evidence or mentioning of Burter's sexuality by the other characters.
Cooler is occasionally referred to as a prick by Frieza.
Goku apparently thinks Krillin sounds like a duck: on Namek he screams and Goku thinks it's a duck, then Krillin quacks and Goku knows it's him.
Frieza doesn't sound like an old hag like in the original dub (although in the Bardock Special there's a moment he does, and he explains there's something in his throat).
Frieza gets a deeper voice when he transforms into his 2nd form. When he's in his 3rd and 4th forms, he's back to his higher-pitched voice. In the original dub, he didn't get his high voice back until his 4th form.
When Vegeta tells Krillin to wound him, Krillin does it without hesitation after Vegeta said he will not punch him (though when wounded he yelled 'You are so punched!) while in the original Krillin hesistated for a long time. Along with that, it happens before Gohan attacks Frieza in his third form while in the original, it happens after.
In the original series, Vegeta cried his soul out to Goku in his dying last moments as he revealed that it was Freeza who enslaved and destroyed the Saiyan race. In the Abridged series, Vegeta didn't shed a tear and simply told Goku about Freeza's crimes against the Saiyans (Though he claims he still would have been just as evil as he is now even if Frieza hadn't made him a slave). He also succumbed to his wounds after realizing that Goku is the last Saiyan in the universe (And therefore, the most stupid).
In the original show, God states that Earth's Dragon Balls have a one year limit on wishing many people back to life, no such thing exist in the TFS, therefore all saiyans except for Toma, Selypa, Pumbukin and Totappo are wished back only to die again (they died on planet Vegeta)
Dende also transported everyone on Namek, except for Goku and Frieza, to Earth before finding out King Kai's plan; in the original, Dende was told by King Kai about the plan before doing it.
Unlike the original filler, the Garlic Jr. saga only lasted one episode. Mr. Popo single-handedly defeated Garlic Jr. by eating him and his minions when they invaded The Lookout.
Garlic Jr's minions never got any dialogue, instead having the voices and cries of Valve's Team Fortress 2 characters instead.
Maron initially behaves like the promiscuous version of her in the original anime, but instead of staying that way, she reveals that she was an undercover IRS agent trying to expose Krillin for insurance fraud.
When Frieza and King Cold come to Earth, they continue the running gag from Season 2 as referring to typical Earth locales as "Space" locales (i.e., Space Radio Shack.)
In the Abridged version, King Cold refers to Frieza as a "princess" multiple times.
In the Abridged version, the back of Vegeta's pink shirt has multiple slang terms for homosexual which change every scene.
In the original, It is known that Future Yamcha was killed by the Androids along with the other Future Z Warriors. But however in the Abridged version, It is revealed that Future Yamcha hung himself after finding out that Vegeta got Bulma pregnant.
Bulma's impregnation by Vegeta is accidental (due to him not wearing, or even knowing, what a condom is.) In the original, it was due to a mutual attraction between the two, not a one-night stand.
Goku's heart virus is changed into clogged arteries due to his love of food.
Unlike in the original where Vegeta turned Super Saiyan when a meteor was going to hit his ship, the Abridged version has Vegeta throwing a tamper tantrum and somehow unlocks his Super Saiyan form
In the original, when Gohan is about to rush towards Piccolo as he is dying from Cell, Goku punches him to stop Gohan from heading out. In the Abridged version, Goku only holds him down while successfully managing to convince Gohan on why he should not rush to his death.
Perfect Cell introduces himself with a song. He does not do this in the original version.
In the original, Future Gohan clearly loves his parents as his mother is seen being worried about his son as if he knows he is fighting the Androids while he wears his father's Gi as an inspiration in hopes to become like him. But in the Abridged version, he disowns both his parents, never speaking to his mother and cares little for his father with the gi instead being the only gift left from him.