Umbral Ultimatum, finally. Sorry for taking so long with this, but damn was it hard to record - this is the best version I managed to get, and although I'm still not totally happy with it, I figured it was good enough to upload.
For those of you who don't know, this is Umbral Ultimatum by Toby "Radiation" Fox, from MSPA's Homestuck. This was a combination of memory , ear and sheet music (Radiation was kind enough to supply the midi, without it I would never have been able to do the koto solo).
For the koto solo, I simply layered a koto over the piano, so that the base octaves at the end could be sustained. And I also reprogrammed a pedal to pitch bend, so what's happening at the end was a live part of the performance (not sure why it starts buzzing though, sorry about that).
And yes, I'm pounding the first note out of frustration from recording for so long. And curiously enough, the hardest part was the piano from 1:48 (not the koto solo, nope)