The thing I despise about Synthesia is that it packs the decay of notes into the duration of the note, rather than starting the decay when the note is over (at the noteoff, that is). That causes all notes to sound shorter than intended, given they were originally written for proper synths.
Each DOOM and DOOM II song? This is only way to do it, with MIDI files. I will get right to it :D. But don't worry if it takes me long. These old MIDI files are pesky to find and assemble