"Squirming Evil" is approximately one minute and fifty-four seconds long in Kingdom Hearts. In the HD remake, the piece is one minute and fifty-six seconds long.
The in-game versions have a time signature of 4/4 time and a tempo of 160 beats per minute.
The piece has a four-measure introduction consisting of strings, low brass, percussion, piano, synthesizer, and woodwinds. The tone throughout the piece is tensive and ominous. Being a major boss battle theme, the piece is typically louder in dynamics- at the minimum, a forte- and very percussive and brass heavy. The woodwind- in this case, flute- flourishes that interrupt throughout the piece only serve to heighten the tension. The instrumentation for both versions consists of: strings, woodwinds, brass, piano, synthesizer, drums, and crash cymbals.
