Zanzlanz shipped a browser game called Crow Sign. The repository holds no PNG, no TTF, no MP3. Every sprite, glyph, sound effect and music loop is rebuilt at runtime from sine-wave coefficients. The whole game is 455 KB.
The trick is the Fourier series. He built a drawing tool: sketch a shape, transform it into the frequency domain, keep the coefficients, throw the drawing away. The game renders by adding the sine waves back together. A slider drops the high frequencies, and that slider is the compression. Fonts are 26 cursive letters drawn the same way, so the text can wiggle and fade in stroke by stroke. Sound is synthesized from scratch: ADSR envelopes, pitch slides, and three layers of FM modulation to fake white noise, which he calls the sine wave's arch-enemy.
What hooked me: an NPC's shape and its voice are the same coefficient set. One datum, two renderings. And the gameplay loop is shaped like a sine wave on purpose. Meet a neighbor, take a request, collect letters, fly the banner, meet the next neighbor. No branching, no failure state, it only moves in one direction.
Video: How I released a game that has no assets. Play it: zanzlanz.com/g/Crow_Sign.