I adore this~ But I would like to have a few critics none of them are like YOU DID THIS WRONG but like my opinions on the song. I really like how you had a solo character with a duet song, saying that it kinda bugged me watching the character lip sink both parts- What I picture when I hear this song is a shy, innocent girl/boy being tempted by a demon/evil person to come to the dark side, thus why the lead singer talks about being worse than death in the end of the song. I think it would be cool to go back to this and instead of having the girl sing both parts, have like the background voice (whichever you think is background, I personally think the second voice stays as background through the song) and have the character stop and like close their eyes or look around in fear, thus showing that something is tormenting them, but they cant see it clearly. the other thing that i can see but I dont really care if you fix is it feels like the characters movements are too jerky. (As a newbie mmd'er I know how hard that is to do) So maybe you could practice making the movements more fluid with the music instead of seeming like they are for a different piece.
looks great but try using the info thing(the one that counts your frames and what time is it on) to time your motion and use the play with frame thing so your motion can be on time with the song, but this still looks good for a begginer ^^