You say you were trying to make it work for challenge C but with the echoes of most of the instruments it would definitely not sound the same reversed as it does going forewords.
I won't dock points or anything since it's still palindromic just pointing it out.
I think the lack of much percussion noise makes this track feel odd. The really sharp melody has nothing to counter it and it just ends up feeling barren.
Adding different melodic lines and more percussive noise would help a lot I think.