The music systems of Plants vs. Zombies evolved over time and are the result of several phases of iteration and reinvention through game development. This talk is an in-depth look at the experiments that shaped these music systems initially, rebuilding the entire score using custom-recorded MIDI sample banks halfway through, and continuing to tighten the link between music and gameplay all the way up until the game’s release.

The guiding principle for the music of PvZ: Heroes was to support the gameplay first and foremost. We wanted music to dynamically track gameplay more closely than previous PvZ games, and switching genres meant room for some fairly big stylistic departures. Extensive prototyping eventually led to a “Saturday morning cartoon” vibe with exciting music and systems being created making the game feel punchier and more alive.

Source: GDC