Hey congrats for being part of that contest. I really hope you had fun mixing the song and you tried things here and there so you get more confident now.
The artistic view you chose are very bold to me and it could work if the client would so. Why not after all.
But as you said, you did the mix more for you than for a listener with way different tools to hear than yours. For instance, say two people listening to your mix sharing earbuds: one get more vocal than the other…
Trying to make the song work while mixing in mono is very difficult but you create more separation that way. And it works also when you turned back in stereo.
Mixing-wise, I agree with previous comments
The only thing that was not mentionned is just before the solo, I found the drums very squashed and the crash cymbal sounds very odd to me.
By the way, strong job to me, very personal.
I now wish to listen to something revised regarding feedbacks and get a your work enhanced!