It isn't hard to come to the conclusion, reading about D&D online (particularly among the old school blogs) that the musical backdrop to D&D for a lot of people was, and still is, 70s and 80s metal. I think Richard G is right that this probably had some influence on making the game a bit less whimsical and a bit more serious over time. I would add that it probably also made things self-consciously "darker" and "edgier". This was a trend against which there was eventually a bit of a reaction, in the form of AD&D 2nd edition, but the metal aesthetic also remains a strong "dark and edgy" sub-current (super-current, really) within the hobby to this day.
(I also think the case can be made that metal influenced not just D&D but the fantasy genre in general from the 1970s onwards - or perhaps influenced the fantasy genre through D&D. At the height of popularity for The Lord of the Rings in the 1960s, fantasy was hippies wearing sandals. By the 1980s it was chainmail bikinis and battle axes. Was that because of metal, or was the success of metal a bi-product of it?)
Those trends were never in my cultural context, though. I was 13 in 1994, and I would say that was the beginning of peak D&D, for me (peak Warhammer too, and peak Shadowrun, and peak Cyberpunk 2020 also....). For the next 3 years that sort of thing was my main hobby. But the soundtrack to those years was not metal. 1994 was the end of grunge and the beginning of Britpop, and it was that strange mixture of influences which formed the context in which I was playing games. The backdrop to my D&D years was in large part stuff like this:
It was Tricky and Massive Attack. It was Radiohead when they were still writing songs and Thom Yorke wasn't quite such a sanctimonious knob. It was the American grunge scene that was still around, like Soundgarden and Pearl Jam and Nirvana (who people were still, of course, listening to). It was dark, in its way, but I think more than being dark the overwhelming vibe is better described as depressing. In 1994 it was cool to be depressed.
That fit in with Warhammer almost ideally: a bleak musical backdrop to a bleak setting.
Yet on the other hand there was also this:
And because I had an older sister who was the one in charge of music in the house or in the car on family trips, it was also this:
All of this stuff was in the air constantly in those days. The mid 90s was the point at which Britain began to flex its cultural muscles and look up instead of back. So the cultural context of D&D for me isn't metal just as much as it isn't Tiki. It's greasy-haired pessimism but it is also interested in beauty and in the possibility of optimism. That sounds more than a bit pretentious. But that's the backdrop against which the game took root in my mind.