In relevant part:
“A vestige of the early demo scene is a category of mod music known as ‘chiptunes’, in which composers create fullblown mods using only computer-created sounds, often simply modified sine or square waves and the like. To qualify as a chiptune, the mod must be quite small (about fifty kilobytes or less) and use only ‘hand-drawn’ tones (that is, tones created by the composer) instead of sampled sounds. These mods, while usually having the distinctive bleep and beep quality of transistor-generated tones, are often astonishingly creative and rich in expressive nuances. This kind of mod music remains a viable option for composers, perhaps because it poses particular challenges and limitations while providing a subversive alternative to the bigger and more elaborate compositions that use increasingly larger samples of real-world sounds and are created with sophisticated new tracking programs widely distributed throughout the Internet.”

Both the game-centric and the synthetic-sounds-centric views seem to have some merit to me; I suppose there might even be multiple cultures within the chiptunes scenes of various eras whose practices relate to videogame music to greater or lesser extents.