In terms of chords and melody, Deep Woods is more complex than the typical song, having above average scores in Chord Complexity, Melodic Complexity, Chord Progression Novelty and Chord-Bass Melody.
Deep Woods is written in the key of G Phrygian. According to the Theorytab database, it is the 5th most popular key among Phrygian keys and the 53rd most popular among all keys. The G Phrygian scale is similar to the G Minor scale except that its 2nd note (A♭) is a half step lower. Chord progressions in Phrygian often rely on the major chord built off of this 2nd scale degree (A♭ major) which gives the key its distinctive sound. See the G Phrygian Cheat Sheet for popular chords, chord progressions, downloadable midi files and more!