Vertical remixing (or vertical layering) is a dynamic music technique where a piece of music is composed as multiple simultaneous layers that can be independently activated or deactivated. A calm exploration layer might play alone while walking, then a percussion layer kicks in when enemies are detected, a bass layer adds when combat starts, and a choir layer blazes during a boss fight, all without any jarring transitions because every layer was composed to harmonize with every other layer. The technique requires composers to think architecturally rather than linearly, designing music as a system of compatible modules rather than a fixed sequence.