There's a great distinction between lyrical music and the music used in video games. Lyrical music is designed to be
foreground music...in other words, the music is intended to be heard for what it is. Video game music is intended to be
background music...intended to either elicit or to intensify a particular emotion or train-of-thought attached to another form of stimulation (usually graphics or storyline). Furthermore, the repeating aspect is true...lyrical music, while it does often follow its own self-repeating style, it not specifically designed to repeat itself when the music ends. Video game music IS designed (or should be designed) to repeat itself when it ends or, in the case of non-redbook tracks, just repeat itself period.
You don't even have to be a first year Juliard student to understand these very basic concepts of music theory.
EDIT: Oh, I almost forgot...there is a game out there which outright breaks the unspoken rule that in-game music must never have lyrics...it's called Waku Waku 7 for the Neo Geo. Listen to the music played in Arina's stage...it clearly has lyrics in it.