The wordplay involving Kyoko's "behind" is not nearly as crude in the original. Godai mistakes Kyoko's "moshi", meaning "mock exam" ("Don't you have a mock exam tomorrow?") for "koshi", which means waist, back, hip.
What they have translated as "flunk-out" is "ronin" in the original. The ronin were masterless, wandering samurais; in modern Japan the term is used to refer to a student who hasn't passed his college entrance exams.
At the party Godai does not tell Kyoko "my name is Yusaku" in the original; he just asks her to stop calling him "ronin". She does not learn his first name until she meets his grandmother in Episode 6, and there it is strongly implied that she had believed, up to that point, that Ronin was actually Godai's first name. If that's the case, then she probably takes his remark to her in this episode to mean "don't call me by my first name". From now on she does call him Godai-san most of the time (in the original; in the translation they didn't fix this until much later), but she calls him Ronin at least one more time, in episode 3.
First appearance of the Cha-cha-maru, its owner (whose name is never revealed, being referred to throughout the series as "master", apparently a common term in Japan for people in his trade) and a few nameless neighborhood characters who are seen again from time to time in the course of the series.
There is a double entendre in the scene with Kentaro at the bar which they have not tried to translate, although it wouldn't have been that difficult to do. Basically, after Kentaro tells Godai that he is going to be a successful man, unlike Godai, and yells at him to get out, he starts to say "I will make the manager happy! I know what it takes to make a woman happy! The most important thing in a man is..." At that point Godai exclaims in horror "No! don't say any more!" and everybody stares in embarassed shock at Kentaro for one silent panel, after which he asks innocently "why shouldn't I say that it is important for a man to be able to afford a huge house for his family?", and everybody is floored.
There may be something in the word "tachi", "worth", that Kentaro uses at the beginning of his sentence ("A man's worth...") which suggests the sexual organ, which is obviously what's on everybody's minds as they stare at him. It wouldn't have been difficult to make the joke a little more obvious for an English-speaking audience; for instance, Kentaro could have said "The most important thing a man can have is a big...", and then ended with "...house for his family."
In the original the caption on the first panel on the second page gives the date as January 9th, 1981. (Year 56 of Showa.)
On p. 3 we see what is probably the first appearance of an as-yet unnamed Sakamoto.
The date in the story is February.
The strange thing Mrs. Ichinose is holding over Godai and Kyoko on the title page is not a coat hanger, but an umbrella; or rather, the stylized drawing of an umbrella which the Japanese make with the names of a couple underneath to symbolize that they are an "item". (More of this will be seen later, in the Yagami episodes.) There are, therefore, some obvious romantic connotations to the idea of a couple sharing an umbrella which should be kept in mind for future reference. See also the very amusing episode of Ranma 1/2 about the "umbrella of love", in volume 31 of that series (as yet unpublished in English).
First appearance of Godai's paternal grandmother, who tells Kyoko (and the reader) what Godai's given name is.
For an explanation of the title of this episode, see the notes to the following episode :-)
On p. 19 of this episode, when Godai's grandmother catches up with him, he is shown stammering: "gr... gr... gr... m... m... m...", after which his grandmother "bonks" him and calls him an idiot. In the original, he stammers "ba... ba... ba... ka... ka... ka...", that is, the first syllable of "baachan" (grandma) and the first syllable of "kanrinin-san" (manager). Together they make the word "baka" (fool, idiot), hence the grandmother's reply ("idiot, yourself", in the original).
First appearance of Mr. Otonashi (Kyoko's father-in-law) and Kyoko's niece Ikuko.
"Wasabi" is a kind of horseradish. Peter Van Huffel has this to say about it: "Wasabi (horseradish) is very spicy and strong stuff used to give flavor and taste to a lot of otherwise bland dishes. I've seen it sold often in little tubes (it's green stuff). The shock that Godai got here is as strong and sharp as the taste of Wasabi (that's the meaning of the title). What is also interesting to note: Wasabi has still another use besides giving taste to the raw dish. One of my Japanese friends told me that it is also used to disinfect the raw dishes. As sometimes the raw stuff isn't fresh anymore, the Wasabi has some qualities as a disinfectant."
"The cherry trees have blossomed," the expression Godai uses at the beginning of the episode, has the double meaning of passing the college entrance exams.
Godai is seen smoking a cigarette in a couple of panels in this episode, the only time in the entire series; no mention of this ever made again, either, if I'm not mistaken. (Thanks to the IFJRT bunch, esp. GeNmA, for this observation.)
First appearance of some of the regular neighborhood gossips, who will invite Kyoko to join the tennis club in the next episode.
First appearance of Shun Mitaka.
Mitaka's car would seem to be a "Nissan Gazelle", which you can admire at this link. Until this URL was found, the position of the side-view mirrors had been the subject of much speculation, but, as you can see, it's not that Takahashi does not know how to draw cars.
(Thanks to "Godai-kun" for this info!)
Kentaro's father, Mr. Ichinose, is first mentioned here, although he will not be seen still for a couple of years. (!)
We also find out here what Godai's family does for a living (they run a restaurant).
A "salty dog" is a kind of cocktail.
First appearance of Kozue Nanao.
The story says it's autumn.
First appearance of Sayoko Kuroki (who will play a very important role later in Godai's life), and the rest of the puppet club, including the "president", who will also be seen again later, although we will never learn his name.