Decent, but slow.
I'm going to rate this for quality instead of my feelings towards you (which aren't pretty). First, while the graphics are simplistic, they add to this instead of detracting from it. However, there isn't much in terms of actual animation, but the parts that were animated were done well. Soundwise, the choice not to use sound effects neither helps nor hinders this, but the music needs to be more action oriented when cupid fights the demons. What worked in the very first part in this doesn't translate well in a fight scene. There's plenty of fight scene related music in the audio portal, but chances are that you can't find it there. As for the fight itself, you should have made it much faster and chaotic. However, that would take away from the drama, but that's a price to pay.
What I did like:
-Fresh take on Valentine Flash.
What I didn't like:
-Needed a more battle-oriented music score.
-Not enough animation for 30 Frames per second.
Conclusion: I'm going to be fair and give you a seven, because I'm not a snooty dickhead who thinks he's always right. You said this is not your best work, and it shows.