(Goku is known for grunting and yelling for minutes on end, doing so to charge up his strength. Superman mocks this by calling him a "constipated jock" because when Goku screams, it makes him sound like he is trying to defecate. The term "jock" usually refers to rather unintelligent or narrow minded athletic people, usually teenage boys.)
With the awful animation and the complicated plot?
(Dragon Ball was mostly made in the 1980s and 1990s; thus, it was limited by the extent of animation techniques at the time. It was only released in English in the 2000s, however, many people don't know it was made earlier and simply think the animation is horrible. Superman also pokes fun at Dragon Ball's plot, which spans decades, has hundreds of major and minor characters in most episodes and resurrects so many characters that most have died several times.)
Who's got the rap bombs to drop on Japan?
(To "drop a rap bomb" means that the rapper will "blow away" his opponent with a big, smooth, fast, or otherwise "explosive" rhyme, often by surprise (cf. "to drop a bomb", which is to make a shocking or surprising statement). Superman references the dropping of the atomic bombs on Nagasaki and Hiroshima during World War II, as Dragon Ball is an animé, or a cartoon made in Japan. Additionally, this may reference anti-Japanese sentiments common in superhero comics from the WWII era, when Superman began.)
This looks like a job for the OG!
(This is a variation on the quote, "This looks like a job for Superman!", which is usually said when there is a problem that requires Superman's assistance. Superman asserts himself as the OG, or "Original Gangster", of superheroes because he was first published in 1938, around 50 years before Goku, and is acknowledged as one of the first superheroes in comic history. There is evidence that Goku draws inspiration from Superman, especially in Dragon Ball Z.)
(When citizens see Superman, they usually shout his name. Jimmy Olsen, a young journalist working for the Daily Planet in Metropolis who is known for being Superman's friend, is also finishing Superman's previous line.)
I'm killin' it; you're Krillin it. I'm villainous to vegetables
(Superman is stating that he is currently killing the rap and that Goku is his best friend Krillin in comparison, who is regarded as a weaker character in the Dragon Ball series when compared to the other main characters. Also, all of the Full-Blooded Saiyans names are puns on Japanese vegetables; for example, "Saiya" can be rearranged to "yasai" which is Japanese for "vegetable". Kakarot, Goku's birth name, Radditz, Nappa, Bardock and Vegeta also come from vegetable names.)
Who dance around in hammer pants that hide their tiny genitals!
(Superman comments on how baggy Goku's pants are and that they are similar to MC Hammer's. This line also supports the stereotype that Asians have small penises. Since manga and anime are Japanese-made, Superman says that Goku has a small penis like his creators, and wearing baggy pants would hide that fact. There were also many instances during the very early days of the manga and Dragon Ball anime when the young Goku would expose himself, and being a child, did indeed have tiny genitals.)
My level is incredible! I'm out of your league!
(Superman makes a reference to a Saiyan's power level and says that he is superior to Goku while making a reference to the Justice League, which he is a founding member of. When something is "out of one's league", it lies beyond his level of knowledge, experience, or (infrequently) social class, so there shouldn't be a comparison.)
You want justice? I'll bust this nut up in your Chi-Chi!
(Superman makes another reference to the Justice League. He also references the line "Superman fights for Truth, Justice, and The American Way". He also says that he will have sex with Goku's wife, Chi-Chi. "Chi-Chi" is also a term for female body parts in different languages, specifically "breasts" in Mexican Spanish and Japanese, and "vagina" in Argentine Spanish.)
Greasy, slick emcee from DC!
(Superman says that he is a great rapper from DC Comics, the company that owns him. Greasy alludes to Superman's typical greasy slick hair style that he usually has a curl in.)
With one breath, I'll freeze your whole measly species!
(One of Superman's powers is freeze breath, but what he could also be referencing is Frieza, a Dragon Ball Z villain, who almost destroyed Goku's entire species and blew up his planet. Freiza is a pun on freeze or freezer.)
You're primitive and limited. You live in a village of idiots!
(Growing up, Goku lived out in a forest alone, rather than growing up in a town or city, so he was unaware of a lot about the world, even not knowing what a girl was until he met Bulma. Also, during his adult life, he resides in the Ox King's village, whose other inhabitants were once fooled into thinking that an imposter wearing a very crude Goku mask was the real Goku, thus, he lives in a village of idiots. He also had a monkey's tail as a child and once transformed into a Great Ape, a form Saiyans turn into during a full moon. Limited is used to say Goku is less endowed than Superman. Goku is also a low-level Saiyan, who tend to be unable to become as strong as Elite Class Saiyans and unable to control themselves in their Great Ape forms. He's also somewhat of a dolt, despite being incredibly powerful. This would make him "primitive and limited". Lastly, Superman notes that the Z fighters, Goku's companions, can often appear to be less intelligent with their powers compared to Goku, who does the fighting for them.)
Step in Metropolis, I'll snap a carrot, period!
(Metropolis is the bustling city (which Superman mentions to contrast his residence to Goku's village) where Superman, as Clark Kent, works at the Daily Planet. As all the names of full blooded Saiyans are puns on vegetables, Goku's birth name, Kakarot, comes from the word carrot. Superman says he's going to snap Goku in half like a carrot if he tries to visit Metropolis.)
How many times are they gonna rewrite your story?!
(Many events in Superman's life have been retroactively added to or removed from his story, which DC has been known to do for its characters by changing their continuity. By contrast, Dragon Ball does not do this for their plots.)
Your powers have been boring since the nineteen fucking forties!
('Although he first appeared in 1938, the 1940s is when Superman began to become very popular. "Forties" also rhymes better with "stories" than "thirties" does. Because Superman is so popular, most comic book characters have at least some of his powers, to the point that many call his powers generic. Goku says that this makes his powers boring. However, Goku also shares the "generic" powers of superhuman strength, durability, speed and flight with Superman.)
(Krillin calls out his name. This parodies the call of "Superman!" earlier.)
Defeat me with heat beams? You're crazy,
(One of Superman's powers is heat vision, where he releases solar energy through his eyes in the form of focused beams. Superman tried to use it on him after his last line, but failed to do any more than ruin his clothes. Goku thinks the thought of him being beaten by it is crazy, because of the below reasons.)
'Cause I'm a Super Saiyan! You're a flying Miss Daisy!
(Goku is a Saiyan, an alien race from the planet Vegeta. Some very powerful Saiyans like Goku can become Super Saiyans, increasing their power fiftyfold. Driving Miss Daisy is a 1989 movie about a chaffeur driving and caring for an old woman. Goku says Superman is riding off of Goku in terms of flight and is an old lady compared to him, or that he just helps out old ladies, an act stereotyped to good guys and superheroes.)
You're pretty pasty to be powered by the sun!
(Superman gets his power from the earth's yellow sun. Being in the sun for a substantial amount of time gives you a tan making your skin darker. Goku is asking Superman why, if he is powered by the Sun, he has pale skin.)
You can't flow to Son Goku; I kaio-ken get it done!
(Son Goku is Goku's Earth name, which he was renamed after being adopted by Grandpa Gohan. Goku also uses his full name as a reference to the previous line, as "son" and "sun" sound similar. He states that even though Superman gets his powers from the sun, he wouldn't stand a chance against a Son. Kaio-ken is a technique Goku uses to multiply his strength and speed. This is also a pun of "I can get it done," but Goku uses it to reference the famous technique by saying he raps better than Superman.)
When I see your movies, all I do is watch the clock,
(Superman has appeared in several film, both animated and live-action. Goku calls Superman's films boring, saying that when he watches them, he just looks at the clock instead and watches time go by until the it ends, which people might do if they become uninterested in a film.)
'Cause there's nothing fun about a superhero scared of green rocks!
(Kryptonite is a green, rock-like element in the Superman universe made of pieces of the planet Krypton. Kryptonite can weaken, or even kill Superman if he gets close to it for long enough. Goku mocks Superman for being scared of simple green rocks like Kryptonite and how nonthreatening it makes him appear.)
Look at those panties! (Oh!) You got that camel toe!
(Goku compares Superman's famous red and blue suit, which looks like he's wearing underwear on the outside, to women's underwear. He further refers to Superman as a woman by commenting that his skin tight clothing, which if he had one, would reveal his vulva, which is referred to as having camel toe.)
I'll report to Lois Lane and Superman that ho!
("Superman that ho" is a reference to the rap song "Crank That" by Soulja Boy. Lois Lane is Superman's love interest, as well as a reporter at the Daily Planet. Goku is using the word "report" as a way of saying he is going to meet up with Lois and have sex with her.)
(Ha ha!) Your rapping is weaker than your fight scenes!
(Fight scenes in Dragon Ball are infamously long, often taking an episode or longer to finish. The anime was released alongside the manga, so if the manga was late during a fight scene, the anime's fight would run longer. Because of this, just a few manga pages were often turned into multiple episodes of anime, dragging out the scenes. Also, sometimes, the characters would seemingly not move at all, justified by the fact that they were fighting too fast to see. Superman says that Goku's rapping is even worse than his fights.)
Just one punch and over nine thousand screams!
("Over 9000" is a famous quote and internet meme from Dragon Ball Z (specifically the Ocean Group Dub), in which Nappa asks Vegeta what Goku's "power level" is, according to his scouter. Superman is referring to Dragon Ball's tendency to feature long drawn-out fight scenes where the characters spend more time shouting to reach full power than actually punching and fighting each other. He also compares Goku's rapping to it, saying that Goku only screams out meaningless insults without any lines that actually hit hard.)
I'll make your nose bleed like Roshi sniffing panties!
(Master Roshi is Goku's perverted master and teacher in Dragon Ball, often getting nose bleeds when sexually aroused. It's a popular stereotype done in manga and anime, as Japanese culture tends to focus heavily on facial expressions. If someone is punched hard enough in the nose, their nose is likely to bleed. Basically, Superman says he'll punch Goku's face so hard, his nose will bleed as much as Roshi's does.)
From Z to GT, you can Dragon Ball deez!
(The most popular Dragon Ball series was Dragon Ball Z, and at the time the battle was released, it ended with Dragon Ball GT. This line also references the Dr. Dre song "Deeez Nuuuts", which has become a running gag throughout the Epic Rap Battles of History series.)
Don't lecture me about fights, you caped coward!
(Goku says that even his fights are better than Superman's. Superman, unlike Goku, does not seek out fights and rarely uses his full power, making him a coward in Goku's eyes. Superman always wears a red cape.)
You got your ass beat by a bat with no powers!
(Superman was beaten by Batman, who has no superpowers (another trait of his which was noted by his opponent, Sherlock Holmes), in The Dark Knight Returns comic. This may also be referencing the previous line; Goku calls him a caped coward, which sounds similar to "caped crusader", a nickname for Batman.)
There's only one way that this battle's gonna end:
(As they are nearly matched in power, Goku says that there is only one solution to end the popular debate between them, which he explains in the next line. "There is only one way this is going to end" is the exact phrase General Zod said to Superman in the 2013 film, Man of Steel.)
One more Superman who's never gonna walk again!
(Christopher Reeve, the third major actor to play Superman in live-action film after Kirk Alyn and George Reeves, fell off a horse on May 27, 1995, after which he became a quadriplegic and was physically immobile. Reeve passed away from this injury in 2004. Goku believes that the only way to end the battle between him and Superman is to beat Superman so bad that he won't be able to move anymore.)