Anything can be an instrument, people—including a whole bunch of floppy drives!
Sixteen, in this case, to be exact. (You remember floppy drives, right?)
You might recognize this tune as "Those Who Fight Further," which is the boss theme in Final Fantasy VII. Here's the original, for comparison's sake.
Pretty close, right? Kudos to MrSolidSnake745 for making the floppy version, forreal.
FF7 - Those Who Fight Further on Sixteen Floppy Drives[MrSolidSnake745]