In terms of chords and melody, Mega Man Zero 4 - Promise - Next New World - is more complex than the typical song, having above average scores in Chord Complexity, Melodic Complexity, Chord Progression Novelty and Chord-Bass Melody.
Mega Man Zero 4 - Promise - Next New World - has sections analyzed in the following keys: D Minor, and D Major. Click on the linked cheat sheets for popular chords, chord progressions, downloadable midi files and more!