Man I played Operation Neptune a lot when I was a kid. I wonder if it was the first game to do this style of adaptive music layering. It predates the iMUSE system used in LucasArts games like X-Wing and TIE Fighter.

For anyone curious, you can actually play it here: https://archive.org/details/msdos_Super_Solvers_Operation_Ne...

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compiler-guy 3 days ago | parent [-]

The arcade classic Space Invaders had a primitive soundscape in that every time the remaining invaders advance, it plays a short bass note. As fewer and fewer invaders remain, it takes less time for them to advance, and the note repeats faster and faster, it adds a remarkable amount of increasing tension as each level progresses.

So not exactly the same, but perhaps prototypical. I think Asteroids did as well.

	▲	mrandish 2 days ago \| parent \| next [-]
		Interesting Space Invaders Trivia: The game speeding up as invaders are eliminated was an unintended consequence of the hardware running full speed to draw all 55 invaders. As invaders are eliminated the draw calls finish faster and the game speeds up. There is no code in the game to throttle the speed. The 2 Mhz 8080 is always drawing full speed. It's delightfully serendipitous this happens to ramp up the difficulty as you near the end of each level in such a compellingly perfect way. (https://www.tomshardware.com/video-games/retro-gaming/space-...) I've watched some interviews with the game's programmer Tomohiro Nishikado and, although translated (so subject to garbling), he seems to confirm this was a 'happy accident'. He indicates he set the max number of invaders based on what the hardware could draw but there was no intent to have the speed ramp up. Of course, he noticed that it did this during play testing but decided to keep it that way. Arguably, it's one of the most compelling aspects of the game. Modern emulators have to add code game-specific code to limit the speed or the game plays too fast. Leaving no CPU cycles unused is the sign of an elegant design.
	▲	chrisweekly 2 days ago \| parent \| prev [-]
		That reminds me of the music in the film "Inception", in which the extremely low-register bass-heavy music in the background of scenes from lower levels of dream-in-dream is actually the main score, played back dramatically (and semantically / thematically) slower and lower.