What's the processing on this 800% slow version of Fear the Reaper?

Jan Igger

New member
So I found myself digging this little gem
and now I am trying to reproduce it by grabbing the original
and throwing it into Reaper (duh), and slowing down the beat 8 times (setting audio playback to 0.125). However the result is kind of squeaky and terrible overall - see this.

So, I guess it's not just a slow down, there's some (a lot of?) processing done and I have no idea what it is exactly. Any clues?