Discussions about great pieces of video game music come up often in the gaming community, but it isn't often that casual fans discuss music theory. Over at the always interesting Ask Metafilter the question has been raised as to which classic video game tunes are in 3/4 time (that is, a waltz). Some of the answers may surprise you if you know your music by hearts but yet never really analyzed it.
In Final Fantasy IV (II here in the US), "Into the Darkness" (the cave music), "Trojan Beauty" (the theme for the castle near the black chocobos), and "Dancing Calcobrena" (the dolls in the dwarf castle) are all 3/4 time. "Melody of Lute" (the song Edward plays) and "Illusionary World" (the land of summoned monsters) all have that funny may-be-3/4-may-be-4/4 quality. Gradius III has a song like that too, "Underground" (the second part of level 3).
Probably the best early example of a game music waltz is the underwater theme from the original Super Mario Bros. (you know, the music from World 2-2 and World 7-2). Useless fact: the next time you watch the 1989 movie Batman, listen for Danny Elfman's "Waltz To The Death" theme. The first few seconds or so are identical to the Super Mario underwater theme. It can be quite jarring to watch Batman and the Joker fight on the top of Gotham City's cathedral as the whimsical underwater theme strikes up for just a moment, as if two distinct fictional powerhouses are converging briefly where they don't belong.