good instrument choice, remains faithful to origin
what did it for me, for this piece, was mostly the choice of instrument. the instrument you chose- (harpsichord or clavichord?) gave it a very baroque feeling.
this feeling of antiquity was further brought out by the left hand, as the regular plodding chords in the first part gave it the feeling of a classical dance, then the arpeggiation at the climax was very regular, although i'd say it was a tiny bit overdone. the ending to the piece was very lovely, it had the feeling of a furious dance again. however, it might have been a little too lively for a finishing bit.
one strange thing i found was the deep bass ring at 0:24 and 0:58.
still, it's a wonderful choice of instrument, and goes with the melody exceedingly well. the classical dance feeling suits both the melody and the "feel" of the whole song. you don't experiment much here- the arpeggiation in the left land is from the original song- but the final effect is very good, and i actually prefer a faithful take using this instrument.
although i didn't feel it was very original or diverse, the clarity of the recording suits the sharp sound produced by your instrument, and your overall is much higher than the average because of the "feel" you create with the song.
on another note, there are two other remixes of lilium on newgrounds. i'd ask you to listen to the "lilium cover" version, it's very good, and has many similarities with yours.
it also starts out with plodding chords, but after that it is very experimental. also, it is a solo piano piece. listening to yours and his side by side is very nice, as they are very different in effect. still, it goes to show that the lilium theme is very versatile.
in conclusion- very good, whether on purpose or not, your choice of instrument fits very nicely with the setting of the original song, and the faithfulness to the original mood and feel in this case is very well executed and in place. still, go search the audio portal for "lilium" in the details, and you'd be pleasantly surprised comparing your piece to others'.