C:\>DEFRAG

Decoded Text From Bandcamp

SOLVE THE PUZZLE.
GET BONUS MATERIAL.
MBRSERVER.COM/HELP

Backward and forward we walk in a line
Over a square made of space and time
Behold the numbers sometimes can lie
Not all of them in order you'll find.

Clusters of data.
Sectors and files.
Over and over.
Need to optimize.
Reading and writing.
Sorting and wiping.
Staring and waiting.
Sometimes frustrating.

When all the matrix is clear in your mind.
All of those numbers are easy to find.
Just look around. No need to grind.
Because the answer is all in plain sight.

Put them together. Clear all the spaces.
Cracking the code has never been easier.

Open the gate.
Redeem the prize.
Access is granted.
Download the files.

The Base64 portion is AES-256 encrypted, with the key: "362934313335323730"

The
36   34

32   30
is visible in the "disk.png" image (scratched into the surface of the floopy disk).
(It looks kinda like 56 and 3A, but it's not. And, it's not ASCII either.)

Construct a magic square like this:
36 29 34
31 33 35
32 37 30

Concatenate all of these digits, left to right, top to bottom, into a string (without spaces), and that's the AES key.