Alas, a fate worse than death has taken thee.
Some background: In Japan, the first two Dragon Quest games did not have battery saves, they had passwords ("Spells of Resurrection"). Losing progress this way was certainly possible, but it was a different kind of despair entirely.
Dragon Quest III was the first to have save files. But these saves were rather prone to corruption (or at least failing to successfully read, which was interpreted by the game as corruption and led to deletion), resulting in the "curse" jingle over the message "Regretfully, Adventure Log _ has vanished." The message has since become rather infamous among Japanese players. The English translation of the message has varied, but I went with the one used in III.
(Note that in this video, it says "zannen desu ga" at the start, whereas the actual message says "o-ki no doku desu ga." Pretty similar meaning, but I'm not sure why they made this different when "Death should not have taken thee!" was identical.)
The first Dragon Warrior didn't come out in English until after DQIII was out in Japan, so the English releases of I and II basically lifted the save system from III and made things fancier. However, the first two games don't have any jingle to go with the message.
Under each party member's HP and MP on the battle screen in the first verse is (the first character from) their class: Soldier A, King, Mage, and Priest.
Do I need a note for this...? Uh, shogi is a Japanese equivalent to chess, and like chess, it has a king piece. If it hadn't been explicitly shown in the video, I would've just said "chess," but... yeah.
The "Yah! Yah!" part was a pun I couldn't really translate on how elderly speech in Japanese has a lot of "ja"s in it, mostly at the end of sentences, so King Rin repeating it a lot makes the chorus shout "jaa" in the "well then" sense, leading into her "what do we do?" line.
Speaking of "King Rin," while this song does say "king" in English twice, a character bio for the DSNHTT! novel (yeah, there's a novel, and a second one coming out, no I'm not translating them) confirmed she's a girl - ahem, LADY. (She actually crosses out "girl" and writes "lady.")
Original video: http://www.nicovideo.jp/watch/sm24909819