Now playing on YouTube:
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Dream Theater's "Panic Attack", rendered entirely on an American NES system. This version actually plays completely on a default, unmodified NES with no expansion chips. (I have a CF-card/NES cartridge combination that lets me do this.)
I transcribed it using FamiTracker for Windows, and it took about 10 hours total, spread out over a week. I also drew up the 8-bit version of the Octavarium album cover in something like 20 minutes using MS Paint. :)
Yes, I have too much time on my hands. Your point? :)